My social networking sites are four: Facebook, Twitter, LiveJournal, and Gtalk (it counts, okay?). Each serves different purposes by different media, to different audiences of differing size. They're each alright in their own way.
Facebook is my public facade. What goes on there is carefully screened and composed to be, I hope, perhaps not the most honest picture of who I am, but a decent sampling. Twitter... I don't even know. It's mostly just "for fun." I may stop using it. LiveJournal used to be a place where I could talk about more personal things, but circumstances and friendships change, and now that's not the case so much anymore. I wonder if sometimes these are things that I should get out in written form, but keep to myself; hence the Little Black Notebook experiment. Gtalk is for more intimate socializing. It is here that I do the most switching of my masks, depending on to whom I'm talking, often a number of masks in a few seconds or several at once.
Sometimes I feel like I'm just talking to be talking, and not because I have anything to say. For example, I didn't want this post to turn out so long.