there's a star above my username

I had a question regarding why some people have a star while others don't? The response received was that everyone gets a star at 100 posts. Because now I have a yello one with an 8, I just assume that if prople are rating your post positive, you get numbers up. If they rate it negative, it goes down. There are those with no star at all - I just guess they had lots of negative ratings. I was also told that there are people requesting negative rating - beats me in ubderstanding why...