I just noticed i had that badge.Its for being one of GS's top 1000 reviewers. Apperantly theres also a top 500, 100, and probably a top 1 also. It seems to come from many members either trusting your reviews or giving you thumbs up. (probably the latter because i only have four trusted people.) Anyway i think its rare because i have only seen two people other than myself on GS with either one of this type of badge. There is obviously 1000 of them but who cares. :P