Google acquires Bump. It's not the "bumping" that's valuable. It's figuring out two people are in proximity to each other that allows them to bump - that's Gold.
Here is a view of the web interface that I would use to demo/test the API: http://i.imgur.com/tQA35U8.png
I still can't figure out a product for the thing, but if you have an idea, hit me up :)
But then, you go on to speculate not just that it's probably not technically difficult, just "clever", and then go even further to speculate that it's probably "not exactly a technology that seems worth acquiring." Are you asking questions in good faith or are you making claims? What you wrote here seems less a genuine question and more a post to downplay bump's work and their acquisition as worthy.
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.
Now what is note-worthy here is that the signatures wouldn't be "identical". They may not even be opposite as i think the idea is to bump your HANDS while holding them, so the hands may distort the vibrations. So the fact that they actually managed it to WORK is astounding.
A few years ago a bunch of users in an BBS were playing with the app by bumping alone and see who the algorithm would pick as a match in their town. I guess it got better, but at that time you had something like a one in five chance to get a match in downtown areas.
Dunno if that was actually the case though.
http://www.google.com/patents/US20110191823
Looks like they took out some patents on fixed buttons as well.
http://www.google.com/search?tbo=p&tbm=pts&hl=en&q=inassigne...