I think that a lot of the time I will act a lot different online that I would in person. I think I get a little too nervous to say somethings outloud or don't have the time to think that quickly and react when I'm face to face with someone who I like. I'm a pretty shy girl around the guys I like too. On myspace/facebook I might comment more or do smiley faces or just try to say witty / cute comments. Sometimes its a little awkward when I see them in person after that because you aren't embarrasssed necessarily by what you said, its just hard because you know you don't act that way in person, especially if you don't talk to them that often
When I talk to a guy in person then I might be extra nervous. Blush more often, afraid of eye contact at first, my hands shake, my voice shakes. haha I dunno
I guess if you are interested too then you gotta show it to her, talk to her more, cute comments back at her. that will make her feel more comfortable with you and get her less nervous and open up.