The ability to award extra rep or a badge to users who make some kind of great contribution, kind of like the Wikipedia [Barnstar][1] idea.

**Advantage** (at least of rep) is that it is completely scalable (e.g. 200 rep awards for 20K users, 300 rep for 30K etc.).

**Disadvantage** because it is subjective some people who don't get these awards may ask, "Hey, what about me? That's not fair" and it may create a bad atmosphere.


  [1]: http://en.wikipedia.org/wiki/Wikipedia:Barnstars