it depends..

usually i jus like to add my two sense and get out. unless im really interested in the topic...

Yeah, it depends. A lot of topics on the forums here ask people specifically about their own experiences or views and are generally more focussed on a general idea, rather than a versus setting. Though there are also a lot of interesting topics which are very much oriented around discussing something.

And then, of course, there's the games section that pretty much requires you to read the posts in front of you. :p

It depends on a lot of factors. If I feel strongly about the topic or not.
If I've been drinking... or perhaps how many drinks I've had before commenting.

Depends.
Sometimes if it's really interesting, and as long as it's not a really long thread.