Peer-to-Peer (P2P) is a model of communication and resource sharing in which each computer (or “peer”) has the same capabilities and privileges. In simple words, instead of having one server central that manages everything, each computer in the network can act as both a client and a server. The concept of Peer-to-Peer is not new and dates back to the early days of computing.
However, it became popular in the early 2000s with the spread of file-sharing software such as Napster, eMule or BitTorrent. Originally, many of these platforms were used to share mostly music files, but today P2P is used in many other contexts, such as distributed storage systems, video streaming, and even cryptocurrency.
Imagine a P2P network as an immense party where everyone enjoys the same “privileges”. Everyone can talk directly to everyone else, without having to go through a central “intermediary”. If you want a file, a song or any other information, you can directly ask another “host” (peer) who has what you need.
This makes the system very flexible and decentralized. Files are directly shared, so they are downloaded from the peer to your computer. On some networks the file can be downloaded by multiple peers at the same time to increase the download speed. But it doesn’t end there, as you download you can contribute in turn by by sharing your files in the P2P network. This system is precisely decentralized; there is no central point of control, which makes this system robust but also difficult to monitor.
In the early days some of the most popular software were Napster (very popular in music sharing), eDonkey2000, eMule, Gnutella, Kazaa, Shareaza. BitTorrent (e.g. uTorrent clients, qBitTorrent, etc.) are currently used instead, DC++, Soulseek, Jami, Zeronet and many others. Napster, recently, has been completely renewed in the form of a subscription-based music platform.
However, although P2P technology, in addition to file sharing, is also used in the area of cryptocurrencies, it is always good to be knowledgeable about possible risks as well: it is good to check always what files you are going to download and whether they come from safe sources (especially be sure whether you hold The copyrights to be able to do so, otherwise you risk copyright violation.) Downloading copyrighted material without permission is illegal and can lead the end user to be sanctioned as well.