RetroShare
Email Alternatives, Instant Messaging, Social Networks

Secure P2P communications platform offering IM, forums, VoIP, file sharing, and more.

Security Notes

Note that RetroShare has not been thoroughly audited by security professionals for possible security issues.

For those of you without a server, RetroShare is probably the easiest way to start your own encrypted social network.

Supported Protocols
GPG
VoIP