Another advantage to reputation is, as has been said, it's replaced post count. If we give rep for intelligent and/or useful posts (my first rep boost comes from BMG! for giving a suggestion on a thread asking for them), that will encourage intelligent and/or useful posts. If we focus on post count, we get stuff like the second, third, and fourth post on
this page.
Psh, "shiney." I don't have to look at post count or join date to know
that guy's a total newbie. He doesn't even capitalize it! And he triple-posted!