Pleroma - Pleroma is a free, federated social networking server built on open protocols.

FriendLife - FriendLife is a great and interesting way of making new and dashing friends for free.

GNU social - GNU social is communication software for both public and private communications.

Twoo - With the millions of active and interesting people around the world, Twoo is one of the most interesting and practical means for finding the new people across the globe.

ZeroMe - Social network for the distributed P2P network ZeroNet.

Qeep - If you are looking for a dedicated application freely allowing you to meet new people and find interesting friends, then Qeep is an application to whom you must give at least one try.