No. But only because I don't know what you look like. And its hard to get a good sense of someone just from what you see of them online, so I'd be worried I was just totally mistaken and actually end up talking to someone completely unrelated.
Now if I met you at a con or something before hand then I'd probably approach you, ask if you wanted to grab some beers, talk about ponies and other manly guy stuff like that. Not that I'd ever see you at a con, since I never go...
It's kind of hard to say. I mean, I wouldn't want to be a nuisance or anything, especially if it's out in public and not a con. Now, were it me, it wouldn't be a bother to me to have random people coming up to me. But the other way around, that's just not how I work. People deserve credit where it's due, but they also deserve privacy. Again, that's just me.
Depends on the situation. If you were with people, I would just stare at you and drool until you walked away. But if you were by yourself and having a coffee or whatnot, I'd probably say hello, and fan-girl squeal and run away and tweet about the awesome experience of meeting you. ^^