Been there, seen that, I was on convention a bit ago (pyrkon, you should recognize), and I can tell you about differences between RL and IL:
There are 3. types of people:
First that will be hating you in internet (I as moderator am hated a lot), but is not going to do a thing when he meets you in real life, and will generally stay cool
Second that will be cool in internet and even better in real life
Third one complete fucktards that will attempt to be idiots both in real life and internet
Unsurprising will be that first type of people are majority, then comes second, and last are exceptions, I've been literally threatened with death, and guess what? Not a single person that did it even tried to do so, more so, some were first type of people, so yeah, people can be total morons in internet, and cool in real life, but there are people that are dumb in both, but there are not as many (seen a few of them)
As for me, depending on situation in real life I can be both antisocial and open, that depends on what type of people I've to deal with (I don't mean friends and non-friends here).
In internet ... that depends on mood