[relix]

The edge cases are enormous - smartphones aren't always running on the same time, and their internet connection delays might be different (one on WiFi, the other on Edge) so syncing time would be difficult. One might give a location based on GPS, the other just the nearest telephone pole. Or maybe none at all, or the wrong one (it happens), or different poles. If you get only 1 bump every 10 seconds it would be easy, but Bump's market probably like to hang out at social events, making it harder to figure out time-wise which bumps are which.

I can go on, but if you can't imagine it being difficult, then your imagination needs work!

I think the hard part of their patented algorithm would be to use data from the accelerometer - basically the only thing that can be 'trusted' - to match bumps up through the unique bumping signature/characteristics. Actually - since it's patented it should be public record, so we could go look it up.