I deleted my facebook. The utility of it was negligable, and my constant issues with the privacy and oversharing finaly made me throw up my hands.

I still have a twitter account, but I rarely use it. I find the reverse-cronological order of short comments makes it irritatingly difficult to peice together coherent thoughts of it's posters. I also don't like sharing with the draconian character limit.

Reddit: A combination of utlity and time-wasting. I have my own private subreddit for passing notes to myself, and I kill a lot of time on the site in general - though I've long since stopped following any of the default subreddits but askreddit, since it's the best time-killer amongst the defaults. Seeing an image macro in any subreddit I follow makes me automatically itch to unsubscribe it. I do use it to keep an eye out for useful utility sites for my writing. I hope to use Hubski for the same purposes - though less of the generic time-wasting, and more utility.

You Tube: Only very rarely.

Any I'm missing? Frankly, the truth is I don't like sharing myself on the internet very much.