How do you add friends on Fanpop?

Hey, sorry if this sounds like a dumb question, I used to be on Fanpop for a short amount of time, and now I've rejoined with a new account. :-)

I have a few friends that I actually know in person who are on here, but whenever I type their username in in the 'Search all of Fanpop' bar at the top right of the page, it won't come up with the person. :-(

Thanks in advance for answering ;-) You rock.