Peer to Peer Network

Often written as p2p. A peer to peer network is a type of networking system that does not requires a central server

Advantages
Peer to peer networks are hard, if not impossible to shut down, due to the lack of an SPOF. ISPs worldwide would need to cooperatively shut down the entire network at once, if only one peer stays up, the network is not to be considered dead. Peer to peer networks usually protect the privacy of users, since there is no registration to join, a given data packet could originate from anybody, make it extremely hard to identify its users and the content they put into the network. Peer to Peer networks are useful for people to retain their right of free speech.

Disadvantages
Peer to peer networks lack a regulating instance, it can grow uncontrolled and since everybody can join anonymously, a p2p network can easily get out of hand and be abused, if it is easy to do. Well known examples are TOR and BitTorrent.