Yeah, there's that, but in my experience most people don't care, and if they do care, they tend to just ask for a picture... cause you know, they wouldn't ask if they weren't at least remotely interested.

Also I always used to find it really annoying if some random person came up to me to ask if i was on "insertsitehere.com", because they saw my picture and recognized me. Doubly annoying if you happen to be out with someone NOT from that site. Also stalkers... they can't stalk you if they don't know what you look like!