I should probably let Ian answer this one.
As far as I know, it's a feature set, within the Forum Software that, based on presets or some manual configuration awards various atrociously named atta-boyz to members for various achievements (longevity, number of posts, various other assorted parameters) and needs to be turned on.
It's relatively harmless but of no particular value either (as far as I know).
I kinda like the fact that this forum remains pretty clean and crisp and stays away from that type of unnecessary bloat.
But again..... that's just me.