MetaSeraphim said:
A form of body language does exist, yes. It is not the same as when in the real world, but once you're able to pick up on it you can basically tell anything about the feelings of the person even over the internet.
I think that's true to some extent, but I think they way we communicate in general changes completely depending on what mediums one uses.
On the internet, there are less social inhibitions because of the factor of anonymity. While we may be able to use an alternative to body language, the way we act and subsequently the way we use such body language changes.
What the internet lacks is the spontaneity of face to face conversation. For this reason, the internet is a slightly less socially awkward place than the real world.
I am not personally familiar with internet body language, which is evident given that I find sarcasm impossible to convey in text form.