I do think deeper and stuff, but I think it's not about how you think, but knowing what they're talking about, and giving your thoughts or knowledge about that.
My friends tend to talk about what they did today, talk about another friend of theirs, gossip, etc... That's why I don't get to talk a lot since I'm not that much on FB myself.
If they were to talk about something I know something about, like sports (or fuck, if they talked about videogames!), then I'd probably be far more talkative. :P
Funny thing is, I'm totally social on places like Steam or GB, yet in real life I feel like I'm really missing out by not bringing out my talkative self. I just can't seem to find my way. Not feeling like getting on FB 23 hours a day, anyway.
We are on the same...I mean, I can talk to someone if I want to, I like my friends and stuff, but it's kinda hard when it comes to carrying on the conversation. That's probably the only thing that's standing squarely in my way. I'm just rusty at talking itself.