Does Facebook hurt actual social interaction?

Why doesn't anyone look at the extrovert/introvert question here? Its soooo much easier for an introvert to post on their own wall "Oh the new Tron was really cool" and then when other introverts meet them in meatspace to talk about how cool Tron was (or wasn't). Whereas those same two introverts in the same room at the same table sharing a meal might not be able (or willing) to surface both that they had watched Tron and they thought it was cool. Because, as introverts, they have an inner fear that if they thought it was cool and the other person didn't they would be negatively judged and things would become awkward.

So from the introvert's perspective I'm sure that Facebook and Twitter has greatly expanded the topics that they discuss with their introvert friends in 'real' life.

That being said, I recognize that intro->extro is a spectrum and I don't claim that folks who consider themselves introverts don't spontaneously start opinion based conversations, I only claim that having established a-priori the opinion space of the other person makes it easier for introverts.

It's a tool, it largely depends on how it's used. It's more of a personal question than one that is best answered by statistics. What you should worry about is whether it increases / decreases your social interactions and how social you want to be. Perhaps you want to be less social and Facebook enables that, perhaps you want to be more social and Facebook also enables that. It really comes down to how you use it. I don't think I've ever thought 'I'd really rather not go out tonight, I'll just find out what happened on Facebook tomorrow.'

For myself I find out about events that I may not have heard of because I didn't speak to that friend that week. I think Facebook is neutral for good friends and increases interaction with friends at the edge of your social circle. It's also a great place to keep in touch with people that you only see at certain conferences, events, etc. It's essential for me for keeping in touch with campmates from Burning Man.