I think that's right.. can't really remember exactly. Yellow members are chosen by me. It's completely subjective and has nothing to do with numbers really. You can see what you're at by looking in a thread you've posted in and looking under your name.
yep, you could do a lot of useless posts, but everyone would think that you are dumb and annoying and it wouldn't be worth it. It is better to post intelligent replies to people's questions and build up your posts that way.