Online, I'm much nicer than I am in real. I can also be a lot meaner, because I know that there will be more support from people online and shit. xD I cuss a whole lot less in posts than I do in real life (I don't know why o_O). But I guess I don't talk online as much as I should because I'm afraid that someone is going to quote me, and make fun of my post, I just seem really stupid (which I do a lot), or unnecessarily long-winded.
I'm the same I think, I just talk a LOT more online. XD
IRL I talk a lot, but just not as much. :p
My personality is basically the same for both. But that is only if you know me well IRL...if you see me as a stranger but knew me online, you would probably not think I was the same person. Also, I'm less serious offline, haha. Not that I'm serious on here very much, anyway. And I talk less IRL than I type online.

I'm really shy online. >.> I try not to talk much, unless I'm helping someone out. Even then, I get nervous. I reread my comments at least twice, for spelling and grammar. But I write like I talk. xD Wich is useful when I'm working on my books.
In real life, I'm very outgoing, though I can be a tad short tempered at times... ^.^;;