Each rank depends on how many posts you have made.
That's all I'm going to say at this point.

It seems posting is going very quickly so I am going to have to reveal a couple of things.

Rank (Stars), Rank Title, Minimum Posts, Reward

0, Newbie, 0, Nothing

1, Beginner Member, 5, Nothing

2, Great Member, 50, Can apply for personal page

3, Well-Known Member, 100, Can make your own groups

4, Ultimate Member, 200, Can apply to be a moderator

5, ?, ?, Can apply to be an administrator

Rank 5 (5 Stars). Title- Posting Whore. Minimum posts: 350. Reward- Nothing
Rank 6 (XD). Title- Massive Poster. Minimum posts: 500. Reward- XD icon as your rank.