Exactly. Foursquare was hardly the first service of its kind. I think most would agree this is potentially a great idea, but it's never caught on. Why not? I'd

Exactly. Foursquare was hardly the first service of its kind. I think most would agree this is potentially a great idea, but it's never caught on. Why not? I'd bet one major reason is that almost nobody has even heard of the previous efforts. You've got to get the specifics right, and you've got to establish it as a popular thing to do. Then lots of fun may ensue.