I would mind the topics though, it goes like this :
Interesting topic > Join
Topic > Join
Topic I know of > Join
Topic I don't know of > stay away from the thread immediately
Topic which I'm not sure of > try and join in, if situation is bad, abort
That's what I do
(my perspective) instead of being a guy who wants to "butt-in" and asks "don't they *insert question*, what's that?, etc", I'd rather just watch (read)
The system have promoted you internally. You can now add a simple signature. It will take a while for you to rank up to be able to customize further such as adding a user banner, adding a signature images, customize font and so on.