Most of them. But a good majority of them a cubs fans because it's the cool thing to do. If being a Sox fan was given the amount of fan fare that being cubs fan is, there'd be a ton more Sox fans.
And I love how some cubs fans jumped on the Sox bandwagon in 2000 and 2005.
The difference is, every time the cubs make it to the playoffs, I root for them, not as a fan, not a Chicago fan either, but as a fan of history. I know how historic it would be if they won. I'd congratulate them and most of their fans if it ever happens, I'm just firmly rooting against it.