I call it the Name Game and joke around about it a lot playing off the obvious.
"Oh, you know BottleHead? Carries and alice-pack, has a guitar and a dog. You know, face tats and shit!" and other stereotypes.
The truth is, it's more of a small circuit than a small world, and it's not uncommon to run into friends or friends of friends. And playing the Name Game is a great way to make new friends. Almost as if having a mutual friend is a voucher for both parties. I don't mind it. I've made a lot of new friends dropping names.
"Oh shit, you know Dirty Rig? Kid smoked all my pot, man!"