Can You Search Users By Real Name?

I hope this isn't a repeat topic, I scanned through a few pages of the help forum with no luck...

I'm fairly sure I've got some IRL friends on the site but I'm having a hard time tracking them down. Is it possible to search by first and/or last name or do we need to know their username? It's kind of frustrating.

Thanks in advance to anybody who knows the answers, or anybody who can relate.