some of the more promising Free Software packages that provide social networking services
Identi.ca is an Open Network Service. Our main goal is to provide a fair and transparent service that preserves users' autonomy. In particular, all the software used for Identi.ca is Free Software, and all the data is available under the Creative Commons
an open source Twitter clone written in Erlang using the ErlyWeb framework
rab your favorite feeds, set preferred layout (i.e. 3- column) and generate a printable newspaper-style document. This is something that would go extremely well with news and lengthy articles.
a blogging engine designed to be very lightweight while retaining functionality. It is driven by PHP and MySQL (with some AJAX thrown in), and has a pimpin’ theme and module engine
If you want to build your own little tumblelogging environment, you can use Gelato, a GPL'd CMS that specializes in tumblelogging, allowing users to easily include photos, video, audio, links, quotes and dialogues within a post