Perhaps it starts like this. Karma-like, if you will.
Mods start to flag certain posts as "good" or "informative." As a person accumulates these flags, they gain permissions to do Special Stuff. They would be able to flag other mmbers (although they would only be able to flag one message a day or something), gain access to Hidden Forums of Doom, and maybe have a special identifier thingy by their name.
I dunno. Might work, give people something to shoot for.