As far as I can remember, when Keith was getting ready to do the "Be Here" tour, he was looking for something sort of "tribal" as an image. An artist he knows (maybe from Oz?) came up w/ the GuitarMonkey idea (obviously the guy had heard Ray Steven's song "Guitarzan"! LOL) and Keith's team had the little guy plastered on everything.
The fans loved it, and the fan club was re-named "Monkeyville". Keith didn't mean for it to be that big of a deal, but that tour and album really cemented his place in the country music scene and he was headlining, so tons of new people ONLY knew Monkeyville. It was one of those things that became "bigger than all of us". LOL
He's moved his tour and fan club stuff away from the monkey, but he won't ever be able to get rid of it. From what I've heard him say about it, he's come to terms with it - "if the fans like it, well, that's great," seems to be his philosophy.