I dont think there is a site/map where this can work at the moment.
Everyone that has been tried just ends up with a bunch of people who post on there and sooner or later quit bocking and then we have a map which has more quitters than active bockers.
Until we have a way to address that issue, I don't see how it can work.
I guess really we need a system that will delete your information after a few months of inactivity and that informs you it is deleting it, giving you the option to keep it there and not get deleted. This might also keep people bocking as it will remind them that they need to get out there and get jumping.
I dont know of anything that can do that without some serious money, dev and resources.