tweedium - Transform your tweetstorms to Medium posts
ChameleON Social - Create your own dating site or social network
Mastodon - Mastodon is a decentralized, open source social network. This is just one part of the network, run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome!
vldPersonals - Full-featured PHP solution for running an online dating site.
TweetDeck in #280Characters - 280-character tweets for everyone [No longer available]
Zodate - Dating software solution.