If I recall (I'm a new moderator), if you've been selected as having solved "x" number of threads, they we feel you're qualified to select a "Best Answer" (not your own, of course). We feel this is a way that every one has a better opportunity to receive the credentials/accolades they deserve as often times, the original poster or even us mods do not respond back in these threads and a deserved answer is not recognized.
Of course, we HOPE that is format is not being abused (and if we see that it is, we will take Perma-Ban action) and that this system works for all of us.
Wolfshadw
Moderator