Ask HN: Location Based Dating?

Hi HN-

A buddy of mine recently told me to take a look a blippy. I liked it, kind of. In any case, I thought that this voyeuristic (or insane sharing) impulse could be put to use for dating. What does that mean? Well I think with user's permissions you could attach to their foursquare, blippy etc. (or use the api if one exists), gather up their recent check-ins/location data, and then compare with other people who have similar habits. People with the highest matches could be recommended first etc. etc.

Yes/No/Already Exists? What do we think?