What's with "I'm a Fan of"

I don't get the "I'm a fan of" sites on facebook. It reminds me of Cuban Gooding Jr boarding the bus and discovering that he's hijacked a busload of I Love Lucy fans. If the person is alive, why wouldn't I just contact them. If the person is dead, well why would I contact them - I find all those Elvis Impersonators a bit ghoulish.
There must be something I don't understand. Obviously thousands of people link together over Star Trek so maybe someone could tell me why it is so bonding to be a fan of Greys Anatomy or whatever. I do however get visiting the script writers' blog and reading about the creation process.
Speaking of icons,I read about this woman who decorated her apartment with pictures of Marilyn Monroe and Scarlett O'Hara. She reasoned that she'd be unforgetable to ex-lovers because she was so associated with those ubiquitous images.
And speaking of Scarlett, one of the southern belle sites said that northern women were foolish to sit in a room and weep over lost loves. According to southern wisdom, the thing to do is to buy a fabulous outfit, get a stunning hair style and go to the barbecue and charm the room so the guy who dumped you will realize what a foolish mistake he just made.