Tweetworks is designed to make micro-blogging more useful for people and businesses. Tweetworks is based on the simple premise that people like to talk about stuff with other people. And it is the stuff (ideas, questions, politics, sports, arts and so on)

Create your own music station for free. Blip.fm is, essentially, a social network for sharing music. A little like Pandora, a little like Facebook, Blip.fm provides a way to explore music and share what you're listening to with friends.

Elgg was started in 2004 with the aim of providing an elegant and powerful solution for anyone who wants to create their own online community. Elgg is free and open source and powers all kinds of social networks - from education and business to martial ar

A resource produced by The Ohio State University Libraries that provides tutorials, guides, and movies on Internet-related topics including email, social networks, web searching, e-books, browsers, and more.

Social media is an integral part of Department of Defense operations. This site is designed to help the DoD community use social media and other internet-based capabilities to share responsibly and effectively, both in official and unofficial capacities.

This guide to Google+ explains the various features of the service. It is updated periodically so that it stays abreast of the current feature set.