I have what I thought was a fairly unique name, but it turns out the combination of my first and last name is culturally common, and so while there aren't many people with my last name, the ones that do have it often share my first name. I learned this when I looked myself up as a kid. I found a lot of us on Facebook and started a group. It was still going strong when I deleted my Facebook account.

Edit: I don't want to dox myself, but my name is Fartin McFartface, however my friends call me Farty.