There are two types of members - one type is based on the number of posts you have made, the other is for the members that help to run the Forum.
So why have a post-based member classification? If you have questions, its nice to be able to ask someone that you can tell have been active on the Forum for awhile. The assumption is that if someone has made lots of posts, they probably have some idea about what is going on. It also helps to identify folks who are new to the Forum and who might need help.
So what are the post-based member types?
Egg - 0 to 9 posts (1 yellow star)
Hatchling - 10 to 99 posts (2 yellow stars)
Chick - 100 to 499 posts (3 yellow stars)
Fledgling - 500 to 999 posts (4 yellow stars)
Old Bird - 1000+ posts (5 yellow stars)