If you imagine an atheist Facebook, you will not be far off the mark of what Atheist Nexus offers. Billing itself as "a social network for atheists, humanists & freethinkers," Atheist Nexus is definitely worth checking out. It could end up being an ideal platform for users to interact, share information, and perhaps even promote their blogs. I first heard about it from Friendly Atheist and just signed up myself. The primary limitation I've identified so far is the small number of members, but membership is increasing so rapidly that this will soon cease to be an issue. In fact, it looks like membership has doubled in the last two hours! Check it out, and you can find me here.