P2P Apps: What Is a Characteristic? & Examples

Peer-to-peer (P2P) applications, exemplified by platforms like BitTorrent, represent a decentralized computing model distinguished by direct resource exchange between participants. Napster's initial architecture highlighted the disruptive potential of P2P systems by facilitating direct file sharing, although it also exposed significant copyright challenges. A defining trait of these applications is their reliance on a distributed network structure, a departure from centralized server models employed by entities such as Amazon Web Services (AWS); consequently, understanding what is a characteristic of a peer to peer application requires analyzing its operational dynamics within this decentralized framework. The core principle of such networks involves each node, or peer, functioning simultaneously as both client and server, sharing resources without the intermediation of a central authority, fostering a collaborative ecosystem promoted by organizations like the Electronic Frontier Foundation (EFF).

Peer-to-peer (P2P) networks represent a paradigm shift in distributed computing, moving away from the traditional client-server model. They have profoundly impacted how data is shared and accessed.

This introduction will lay the groundwork for understanding P2P networks. It will cover their foundational principles and historical evolution.

Defining the Core Concept of Peer-to-Peer

At its core, a P2P network is a decentralized system where each node, or peer, has equivalent capabilities and responsibilities. This contrasts sharply with the client-server model.

In the client-server model, a central server provides resources and services to multiple clients. In a P2P network, each peer can act as both a client and a server.

This means that peers can directly share resources, such as files, processing power, or network bandwidth, with each other.

Fundamental Principles of P2P Architecture

The architecture underlying P2P networks is characterized by several key principles:

• Decentralization: There is no central authority or server that controls the network.
• Distributed Resources: Resources are spread across all participating nodes.
• Direct Communication: Peers communicate directly with each other.
• Autonomy: Each peer has control over the resources it shares.

These principles contribute to the inherent robustness and scalability of P2P systems. The lack of a single point of failure enhances resilience.

Contrasting P2P and Client-Server Models

The distinction between P2P and client-server models is fundamental to understanding the advantages and limitations of each approach.

In a client-server model, the server is responsible for handling all requests and managing resources. This can lead to bottlenecks and single points of failure.

P2P networks distribute these responsibilities among all peers, reducing the burden on any single node.

This can result in improved scalability, resilience, and fault tolerance. However, P2P networks also introduce challenges related to security, resource discovery, and network management.

The Significance and Evolution of P2P Technology

P2P technology has evolved significantly since its inception. The initial applications were primarily focused on file sharing.

The underlying principles have found applications in various domains.

A Historical Overview of P2P Networks

The emergence of P2P networks can be traced back to the early days of the internet. Centralized systems struggled to handle the increasing demand for resource sharing.

Early P2P systems, such as Napster, revolutionized the way people shared music files. While Napster itself was centralized, its popularity paved the way for truly decentralized P2P networks.

Subsequent systems like Gnutella and Freenet embraced decentralization. They allowed users to share files without relying on a central server.

The Impact of P2P on Distributed Computing and Network Design

P2P technology has had a profound impact on distributed computing and network design. The concepts have influenced various fields:

• Content Delivery Networks (CDNs): P2P principles are used to distribute content more efficiently.
• Blockchain Technology: Cryptocurrencies like Bitcoin leverage P2P networks for transaction validation and consensus.
• Distributed Databases: P2P architectures are employed to create scalable and resilient databases.

The principles underlying P2P networks continue to inspire innovative solutions in the realm of distributed systems. As technology evolves, P2P architectures will likely play an increasingly important role.

Foundational Characteristics and Architecture of P2P Networks

P2P networks distinguish themselves through several key characteristics. These attributes define their unique operational dynamics. Understanding these fundamentals is crucial. It informs the discussion of P2P applications and challenges.

Decentralization as a Core Attribute

Decentralization is arguably the most defining trait of P2P networks. Unlike client-server systems that rely on a central authority, P2P networks distribute control and resources among participating nodes. This dispersion creates both advantages and inherent complexities.

The level of decentralization can vary across different P2P architectures. Some networks might exhibit a higher degree of decentralization than others. The presence of super-nodes or indexing servers can introduce elements of centralization. Pure P2P networks strive for complete distribution of responsibilities.

Benefits of Decentralization:

• Increased Resilience: The absence of a single point of failure enhances the network's resilience.
• Improved Scalability: The network can grow without requiring significant infrastructure upgrades.
• Enhanced Autonomy: Individual nodes have greater control over their resources and data.
• Reduced Censorship: Difficult to control or censor due to the distributed nature.

Challenges of Decentralization:

• Security Concerns: Distributed control can make it harder to implement robust security measures.
• Resource Management: Efficient resource allocation and coordination can be challenging.
• Discovery Issues: Finding peers and resources can be more complex than in centralized systems.
• Difficult Governance: Lack of central authority can complicate the establishment of clear rules and policies.

Distributed Network Architecture

The distributed nature of P2P networks is intrinsically linked to their decentralized control. A distributed network architecture means that data and processing power are spread across multiple nodes. Nodes collaborate to achieve a common goal. This architecture stands in sharp contrast to centralized and hierarchical models.

In centralized networks, all resources and functions are concentrated in a central server. Hierarchical networks organize nodes in a tree-like structure. Both models present a single point of failure, and are reliant on the central node.

P2P networks, on the other hand, distribute these functions across the network. Each peer can act as both a client and a server. This creates a more robust and adaptable system. This adaptability is key to P2P's success in dynamic environments.

Network Topology in P2P Systems

The topology of a P2P network refers to the way in which nodes are connected to each other. Several distinct topologies exist, each with its own strengths and weaknesses. These topologies directly impact the efficiency and scalability of the network.

Structured Topologies (e.g., DHT-based)

Structured P2P networks employ deterministic algorithms to organize nodes and data. Distributed Hash Tables (DHTs) are a common example of structured topologies. DHTs provide a predictable way to locate data within the network.

In a DHT-based system, each node is assigned a unique identifier. Data is stored and retrieved based on a hashing function that maps data items to specific nodes. This structured approach ensures efficient search and retrieval.

Structured topologies offer advantages in terms of efficiency and scalability. However, they can be more complex to implement and maintain than unstructured topologies.

Unstructured Topologies (e.g., Gnutella)

Unstructured P2P networks, such as those based on the Gnutella protocol, rely on random or ad-hoc connections between nodes. There is no predetermined structure. Peers discover each other through flooding or gossip protocols.

While simpler to implement than structured topologies, unstructured networks can suffer from inefficiencies in search and retrieval. Queries are often propagated across the network, consuming bandwidth and resources.

The trade-off between simplicity and search efficiency is a central consideration. It governs the design and selection of unstructured P2P topologies.

Hybrid Topologies

Hybrid P2P topologies combine elements of both structured and unstructured approaches. They aim to optimize the network's performance for specific application requirements. For example, a hybrid topology might use a DHT to organize a subset of nodes while allowing other nodes to connect in a more ad-hoc manner.

Hybrid topologies can offer a good balance between efficiency, scalability, and ease of implementation. Choosing the right combination of structured and unstructured elements is vital. This must consider the specific needs of the application.

Overlay Network

P2P networks typically operate on top of an existing network infrastructure, such as the Internet. This is implemented through an overlay network.

An overlay network is a virtual network built on top of another network. In the context of P2P systems, the overlay network defines how peers connect and communicate with each other.

It operates independently of the underlying physical network. This decoupling allows P2P applications to be deployed without requiring modifications to the existing infrastructure. The overlay network is critical. It enables P2P networks to function seamlessly.

Key Technologies and Protocols in P2P Networks

The operational backbone of Peer-to-Peer (P2P) networks relies on a specific set of technologies and protocols. These elements facilitate resource sharing and communication among peers. Understanding these underlying mechanisms is essential. It illuminates how P2P networks function and their performance characteristics.

BitTorrent Protocol

BitTorrent stands out as a prominent protocol optimized for efficient file sharing. It operates by dividing files into smaller pieces. These pieces are then distributed across multiple peers. This process allows for parallel downloading from numerous sources. It vastly improves download speeds.

The protocol incorporates a tracker. The tracker coordinates the peers participating in the file-sharing process. It facilitates the initial peer discovery. Recent BitTorrent implementations have adopted Distributed Hash Tables (DHTs) as a trackerless alternative. These DHTs enable peer discovery without reliance on a central server.

Gnutella Protocol

Gnutella represents an earlier generation of P2P file-sharing protocols. It employs a query flooding mechanism. Peers broadcast search queries across the network. This ensures a broad reach for locating desired files.

Unlike BitTorrent's piece-based approach, Gnutella shares entire files. This can lead to inefficiencies in bandwidth usage. Gnutella also lacks the robust error correction and resilience mechanisms. It is generally seen in more modern protocols. Gnutella is simpler in design.

Compared to BitTorrent, Gnutella offers a more decentralized and less structured approach. BitTorrent utilizes centralized trackers or DHTs. Gnutella operates on a purely distributed model.

Hashing Algorithms

Hashing algorithms are integral to P2P networks. They provide content identification and integrity verification. Cryptographic hash functions generate unique fingerprints. These fingerprints represent the content being shared.

These hashes are used to verify that downloaded files are complete and unaltered. SHA-256 and MD5 are examples of hashing algorithms. They ensure the security and reliability of data exchange.

Moreover, hashing algorithms play a crucial role in security. They prevent malicious actors from distributing corrupted or tampered files. P2P systems can protect users. They can protect users from unknowingly downloading harmful content.

DHT (Distributed Hash Table)

Distributed Hash Tables (DHTs) are a cornerstone of many modern P2P networks. They provide a decentralized lookup service. DHTs allow peers to efficiently locate resources. Resources are distributed across the network.

A DHT operates by assigning keys to both files and peers. The keys are based on hashing algorithms. The network then routes queries for a specific file. It routes the query to the peer responsible for storing the metadata associated with that key.

DHTs offer scalability and fault tolerance. Chord, Pastry, and Kademlia are common DHT implementations. They exhibit different performance characteristics. They differ in terms of lookup efficiency and network resilience.

Routing Algorithms

Efficient routing is essential for data transfer in P2P networks. The goal is to locate and transfer data effectively. This must happen without overburdening any single peer.

Routing algorithms vary depending on the network topology and structure. In structured networks (e.g., DHT-based), routing is deterministic. The query is forwarded along a well-defined path. In unstructured networks (e.g., Gnutella), routing often involves query flooding or random walks.

Proximity-based routing is another approach. It aims to minimize latency by selecting peers that are geographically close or have low network latency.

Critical Considerations for P2P Network Design

The operational backbone of Peer-to-Peer (P2P) networks relies on a specific set of technologies and protocols. These elements facilitate resource sharing and communication among peers. Understanding these underlying mechanisms is essential. It illuminates how P2P networks function and their performance characteristics. However, building a successful P2P network requires careful consideration of several critical factors. These factors include: scalability, resilience, security, and privacy. Moreover, P2P systems are vulnerable to specific attacks, and raise complex legal and ethical concerns.

Scalability in P2P Networks

Scalability, defined as the ability of a network to maintain performance under increased load, is paramount.

Factors affecting the scalability of P2P systems include network size, churn rate (node entry and exit), and resource distribution. A high churn rate, for example, can destabilize routing and reduce resource availability.

Techniques for enhancing network scalability include hierarchical architectures, super-peer models, and optimized routing algorithms. Super-peer models, for example, offload some responsibilities onto a subset of more powerful nodes, alleviating the burden on the entire network. Caching strategies and content replication are also used to improve performance and reduce latency.

Resilience/Fault Tolerance

Resilience refers to the ability of the network to maintain functionality in the presence of failures. In P2P systems, nodes can fail unpredictably. Therefore, fault tolerance is a critical attribute.

Fault tolerance mechanisms in P2P architectures often rely on redundancy and distributed data management. Data replication, where multiple copies of data are stored on different nodes, ensures availability even if some nodes fail.

Strategies for maintaining network availability in the face of node failures include:

• Redundant connections, ensuring that each node has multiple paths to other nodes.

• Distributed data management, using techniques like erasure coding to reconstruct data from fragments stored across multiple nodes.

  Additionally, proactive node monitoring and failure detection mechanisms are essential for rapid recovery.

Security

Security is a crucial, yet often challenging, aspect of P2P network design.

P2P networks are susceptible to various security threats:

• Malware distribution: P2P networks can be exploited to spread malicious software.
• Denial-of-service (DoS) attacks: Attackers can flood the network with requests, overwhelming legitimate nodes.
• Data poisoning: Attackers can inject corrupted data into the network.
• Eavesdropping: Attackers can monitor network traffic to intercept sensitive information.

Mitigation strategies and security protocols for P2P networks include:

• Cryptographic techniques: Encryption and digital signatures can protect data confidentiality and integrity.
• Reputation systems: Assessing node reliability based on past behavior can help identify and isolate malicious peers.
• Firewalls and intrusion detection systems: These can help prevent unauthorized access and detect malicious activity.

Privacy

Privacy considerations are paramount.

P2P networks can be used for both privacy-enhancing and privacy-violating activities. On one hand, P2P can enable anonymous file sharing and communication. On the other hand, P2P can expose users to surveillance and data collection.

Considerations for how users can protect their privacy include:

• Anonymization techniques: Tools like Tor can mask users' IP addresses and prevent tracking.
• Encryption: End-to-end encryption can protect the confidentiality of communications.

• Privacy-aware P2P clients: Software that prioritizes user privacy by minimizing data collection and maximizing anonymity.

  It's important to note that achieving true anonymity and privacy is challenging, and requires careful planning and execution.

Sybil Attack

The Sybil attack is a significant threat in P2P networks. In a Sybil attack, a malicious user creates multiple identities to gain disproportionate influence over the network. This undermines the integrity and reliability of the system.

The impact of a Sybil attack can be severe. Attackers can manipulate routing, control resource allocation, and disseminate misinformation.

Mitigation strategies for Sybil attacks include:

• Identity verification: Requiring nodes to prove their uniqueness using methods like proof-of-work or trusted third parties.
• Reputation systems: Assigning a reputation score to each node and limiting the influence of nodes with low reputations.

Copyright Infringement

Copyright infringement remains a contentious issue in the realm of P2P file sharing.

P2P networks have facilitated the widespread distribution of copyrighted material without the permission of the copyright holders. This has led to legal battles between copyright owners and P2P network operators.

Addressing copyright issues in P2P networks involves a combination of legal and technical measures:

• Copyright enforcement: Legal actions against individuals and organizations involved in copyright infringement.
• Content filtering: Implementing mechanisms to block the distribution of copyrighted material.
• Promoting legal alternatives: Providing users with access to legal and affordable sources of content.

It's important to strike a balance between protecting copyright holders and preserving the benefits of P2P technology for legitimate purposes. This remains an ongoing challenge.

Real-World P2P Applications and Implementations

[Critical Considerations for P2P Network Design The operational backbone of Peer-to-Peer (P2P) networks relies on a specific set of technologies and protocols. These elements facilitate resource sharing and communication among peers. Understanding these underlying mechanisms is essential. It illuminates how P2P networks function and their performance.]

P2P technology's theoretical advantages, such as decentralization and fault tolerance, translate into diverse real-world applications. File sharing, a ubiquitous example, demonstrates P2P's capacity for efficient content distribution. Exploring specific implementations like BitTorrent and Tribler reveals varied approaches to leveraging P2P principles.

File Sharing: The Archetypal P2P Application

P2P file sharing, perhaps the most recognizable application of this technology, disrupted traditional content distribution models. By distributing files across multiple nodes, P2P networks mitigate the bottlenecks inherent in centralized servers. This decentralized approach enhances accessibility and resilience.

The impact of P2P on content distribution is undeniable. It enabled widespread sharing of information and media, challenging copyright laws and established business models. While concerns about piracy persist, P2P file sharing also fueled innovation in media consumption and distribution strategies.

BitTorrent: A Dominant Force in Content Delivery

BitTorrent emerged as a dominant P2P protocol for file sharing, fundamentally changing how large files are distributed across the internet. Its key innovation lies in its swarm-based approach, where users download and upload portions of a file simultaneously.

This parallel downloading significantly accelerates transfer speeds compared to traditional methods. The protocol also incorporates mechanisms for ensuring data integrity and incentivizing users to seed (upload) files, contributing to the network's overall efficiency.

BitTorrent's Impact on Content Distribution Networks (CDNs)

BitTorrent's influence extends beyond individual file sharing. Content Delivery Networks (CDNs) have adopted similar P2P principles to optimize content delivery. By caching content on edge servers and leveraging peer-to-peer distribution, CDNs reduce latency and improve the user experience. This convergence of P2P and CDN technologies underscores the enduring relevance of decentralized distribution strategies.

Tribler: Anonymity and Privacy in P2P File Sharing

Tribler distinguishes itself by prioritizing anonymity in P2P file sharing. Built upon the BitTorrent protocol, Tribler incorporates onion routing and other privacy-enhancing technologies to obscure users' identities and prevent censorship.

Unique Features of Tribler

Tribler's design emphasizes user privacy through several unique features. Onion routing conceals the user's IP address by routing traffic through multiple nodes. This makes it difficult to trace file downloads and uploads back to the original user.

Furthermore, Tribler utilizes a decentralized recommendation system, allowing users to discover content based on the preferences of trusted peers. This social aspect promotes a more curated and privacy-conscious file-sharing experience.

Tribler vs. BitTorrent

While both Tribler and BitTorrent rely on P2P principles, their objectives differ significantly. BitTorrent prioritizes efficient file distribution, while Tribler focuses on user privacy and anonymity. This distinction reflects the evolving landscape of P2P applications, where concerns about surveillance and censorship are increasingly prominent.

Legal and Ethical Implications of P2P Technology

The operational backbone of Peer-to-Peer (P2P) networks relies on a specific set of technologies and protocols. These elements facilitate resource sharing and communication among peers. Understanding these underlying mechanisms is essential. It illuminates not only the technical functionalities but also the critical legal and ethical dilemmas inherent in P2P systems, particularly concerning copyright infringement and intellectual property rights. This section will critically examine these implications, providing a balanced analysis of the issues at stake.

The Central Issue: Copyright Infringement

At the heart of the legal and ethical controversies surrounding P2P technology lies the pervasive issue of copyright infringement.

The decentralized nature of these networks, while offering numerous benefits for efficient data distribution, simultaneously creates a fertile ground for the unauthorized sharing of copyrighted material. This includes music, movies, software, and other creative works, often distributed without the consent of the copyright holders.

The ease and anonymity afforded by many P2P platforms significantly contribute to the widespread availability of pirated content.

This raises critical questions about the responsibility of P2P network operators, users, and the legal frameworks designed to protect intellectual property.

Ethical Dimensions of File Sharing

Beyond the purely legal considerations, P2P file sharing also raises profound ethical questions. Is it morally justifiable to freely distribute copyrighted material, even if it does not directly result in financial loss for the copyright holder? The answer remains complex and highly debated.

Arguments in favor of unrestricted file sharing often highlight the potential for promoting cultural exchange and democratizing access to information.

However, this perspective often clashes with the ethical obligations to respect the rights of creators and the economic incentives necessary for fostering innovation and artistic expression.

The ethical debate surrounding P2P file sharing hinges on balancing the potential benefits of open access with the imperative to protect intellectual property and ensure fair compensation for creators.

Legal Frameworks and Enforcement Challenges

Legal systems worldwide have grappled with the challenges posed by P2P networks, attempting to balance the need to protect copyright holders with the desire to preserve the benefits of technological innovation.

The Digital Millennium Copyright Act (DMCA) in the United States, for instance, has been instrumental in shaping the legal landscape, providing a framework for addressing copyright infringement in the digital age.

However, enforcement remains a significant hurdle. The decentralized and often anonymous nature of P2P networks makes it exceedingly difficult to identify and prosecute individual infringers.

Furthermore, legal actions against P2P platforms themselves have often been met with mixed results, as the technology itself is not inherently illegal; rather, its misuse leads to copyright violations.

Examining Varying Perspectives

The Content Creator's Perspective

Content creators and copyright holders emphasize the importance of protecting their intellectual property rights to sustain their creative work.

They view unauthorized distribution as a direct threat to their livelihoods and a disincentive to invest in future projects.

Copyright laws are designed to provide them with the exclusive right to control the distribution and reproduction of their works, ensuring they receive fair compensation for their efforts.

The User's Perspective

From the user's perspective, P2P file sharing can offer access to a vast library of content at little or no cost.

This can be particularly appealing to individuals in regions with limited access to legitimate sources or those who cannot afford to purchase copyrighted material.

Some users also argue that file sharing promotes cultural exchange and allows them to discover new artists and works that they might not otherwise encounter.

The Platform's Perspective

P2P platform developers often assert that their technologies are neutral tools. They claim that any illegal activity is a consequence of user behavior, not inherent to the design of the P2P system.

However, critics argue that platform developers have a responsibility to implement measures that deter copyright infringement and cooperate with copyright holders to address instances of illegal file sharing.

The Nuanced Reality of Enforcement

Enforcement strategies vary widely, ranging from legal actions against individual users to the development of technological solutions that automatically detect and block the distribution of copyrighted material.

However, each approach faces its own set of challenges. Lawsuits against individual users can be costly and time-consuming, with limited deterrent effect. Technological solutions can be circumvented or may inadvertently block legitimate content.

A balanced approach that combines legal measures, technological solutions, and educational initiatives may be the most effective way to address the legal and ethical implications of P2P technology while preserving its potential benefits.

Key Figures in P2P Development: Bram Cohen

Legal and Ethical Implications of P2P Technology The operational backbone of Peer-to-Peer (P2P) networks relies on a specific set of technologies and protocols. These elements facilitate resource sharing and communication among peers. Understanding these underlying mechanisms is essential. It illuminates not only the technical functionalities but also the individuals who have shaped this innovative landscape, especially Bram Cohen.

This section highlights Bram Cohen, a pivotal figure whose contributions have significantly shaped the P2P ecosystem. Cohen's creation of the BitTorrent protocol revolutionized file sharing and content distribution. His work not only provided a more efficient method for transferring large files but also established a foundation for numerous subsequent innovations in decentralized networking.

The Genesis of BitTorrent

Bram Cohen's journey into P2P technology began with a dissatisfaction with existing file-sharing methods. Traditional systems often suffered from slow download speeds due to server bottlenecks. Cohen sought to address these limitations by developing a protocol that leverages the collective bandwidth of multiple users.

The result was BitTorrent, a protocol designed to break files into smaller pieces and distribute them across a network of peers. Each peer downloads these pieces simultaneously from multiple sources, significantly increasing download speeds.

Once a peer has downloaded a piece, it becomes a distributor of that piece, contributing to the network's overall bandwidth. This collaborative approach not only improved download speeds but also enhanced the resilience of the network.

The BitTorrent Protocol: A Technical Overview

At its core, BitTorrent operates on the principle of swarm downloading. A file is divided into smaller, equal-sized pieces. These pieces are then distributed among the peers participating in the swarm.

A small file called a ".torrent" file contains metadata about the files to be shared and the tracker. The tracker is a server that helps peers find each other.

When a user wants to download a file, they first download the ".torrent" file. This file points their BitTorrent client to the tracker.

The client connects to the tracker and receives a list of peers who have the pieces needed. The client then connects to these peers and begins downloading the pieces. As the client downloads pieces, it also begins uploading them to other peers.

Cohen's Impact on P2P Development

Cohen's impact on P2P development is undeniable. BitTorrent's innovative approach to file sharing has influenced numerous other P2P applications. Its design principles have been adapted for various uses beyond file sharing, including content delivery networks and distributed computing platforms.

The efficiency and scalability of BitTorrent have made it a popular choice for distributing large files, such as software updates and media content. It significantly reduced the load on central servers. This has made it an invaluable tool for content providers.

Furthermore, Cohen's work has spurred further research and development in P2P networking. The concepts introduced by BitTorrent have inspired new protocols and techniques for decentralized data management.

Bram Cohen Beyond BitTorrent

While BitTorrent remains Cohen's most well-known creation, his contributions extend beyond this single protocol. He has been involved in various projects aimed at improving internet privacy and decentralization.

These ventures reflect a continued commitment to the principles of open-source development and distributed systems. Cohen's focus on addressing real-world problems through technological innovation has solidified his position as a leading figure in the P2P community.

Critical Analysis: The Double-Edged Sword

BitTorrent, while revolutionary, is not without its complexities and criticisms. The protocol's efficiency in file sharing has also made it a tool for copyright infringement. This has led to legal challenges and debates over the responsibility of technology creators in preventing misuse.

The decentralized nature of BitTorrent makes it difficult to control the distribution of copyrighted material. This challenge highlights the ongoing tension between technological innovation and legal frameworks.

Despite these challenges, Cohen's contributions to P2P technology remain significant. His work has advanced our understanding of distributed systems. It has also paved the way for new applications that leverage the power of decentralized networks.

So, that's the lowdown on P2P apps! Hopefully, you now have a better grasp of what a characteristic of a peer to peer application is – mainly that awesome direct connection and decentralized nature. Give one a try; you might be surprised how much you like cutting out the middleman!