Those are ranks. If you are new on the forums, you are ranked as a young pup, but as AceKristal said, the posts have a limit until you move up in rank, and the only way to move up is to post...a LOT! Very actice members on the forums are in really high rank. And if you're wondering, that's what the stars mean too!

Many of the names have limits for themselves. Say if you've posted TONS of posts, then you'd be given something like "I live here!" Or something else.

Young pup means that your new in the forms but I'm not sure what the others mean.