RetroShare is a communication tool that lets you:
- chat in real time with friends and friends of friends
- send messages (like emails) to your friends
- participate in forums, anonymously or not
- read “channels” that contain news or multimedia files
- share files publicly between friends
- share files anonymously (WARNING: your direct friends may be able to see what you are downloading, so choose your friends wisely)
RetroShare creates a “Friend to friend” network, which means that your computer will only transfer files and searches to and from a small group of hand-picked friends. You can still read forum posts or get files from someone who is not your friend: the information will simply be relayed by your friends, and their friends, and the friends of their friends…
The advantage of this kind of network is anonymity: no-one knows where a file is coming from or where it is going to. It can also be hard to know who is participating in the network, or even that a network exists at all, at least in “darknet” mode.
The main drawback is slow file transfers: because a part of everyone's bandwidth is used to relay their friends' transfers, you can only download at a fraction of the speed of a typical peer to peer download.