To really appreciate the legal uses of P2P Systems means understanding the different uses it can be put to. There are several, all of which have their own level of importance.
Peer-to-peer File sharing systems is probably the most common system used by the general public. It means using specific software that accesses a P2P system. It is commonly used in instances where people want to share books or other types of media like movies and music. The software has the job of going on a search for other computers that are connected to a P2P network.
Using a P2P system for instant messaging requires using a protocol like Tox. This allows for encryption to take place at both ends. It is implemented again through a specific software that has been designed for instant messaging use based on this type of protocol.
Voice communication can be structured through a VoIP protocol. Otherwise, it can be implemented through a P2P system that relies on a SIP protocol.
New technology is allowing for more advanced application of P2P systems for collaboration. The standard use of a P2P system for collaboration revolved around the ability to share resources. Now it is opening up doors for peers to be able to introduce newer resources to enhance its capabilities.
Being able to retrieve and share information through a peer-to-peer system is one great benefit. However, being able to back up the data is another. P2P software has to have this capability in many instances.
Other important uses for P2P networks include those for sensor nets, distributed computing, and defense systems.