theha.us is an experimental social-network client. It can do Facebook-y, Twitter-y things just fine on its own, and also echo those things out to Facebook or Twitter, making them a part of your existing social fabric.
It also supports many emerging technologies that can do that Facebooky stuff without involving or requiring a central server - you simply follow another site, and your contributions to discussions you join on posts over there actually live here. Over time, the goal is to fully replace the centralized social networks, and make the Internet a network again.
If you'd like to be a part of the experiment, apply to join.