If like me you are approaching 30, but still bump knuckles on a regular basis like a 14yr old kid from LA, then BUMP could be a pretty useful app for you.
Bumping has been used in a couple of popular apps, such as PayPal, but for this sort of thing to become universally popular I believe Apple needs to introduce this as a native feature in the iPhone for sharing contact details. It would certainly eliminate that awkward moment in a bar when it is loud and you try and enter someones phone number. With Bump, you ask if they have it and (or if it becomes native, you just ask TO bump) bump phones. You now have all their contact details, possibly a photo and you’ve not had to type a thing.
If I was a betting man I would look out for this kind of thing to come in with the iPhone 5 (or going off the latest Apple naming with the iPad, it could just be ‘The New iPhone”)