For those of you not familiar with the concept, it's a take on the iPhone application - Four Square. Where you share live posts of your exact whereabouts. I find it too voyeuristic, self-indulgent and most importantly dangerous. Once you post your location, Facebook is clever enough to publish a map with the exact destination. I think it's an excuse for people to show-off all the 'trendy' places they hang out at. People are also dumb enough to publish their home and work addresses online.
This is every stalkers dream come true!