Link marketing with fanaticsm

I read about how Major Baseball League sold more than 1M cell phone wallpapers, ringtones and other downloadable contents. So what drives this activity? I think it how we connect between marketing and fanaticsm. If someone is so fanatics about something then he/she will dress-up all his/her life with the things related to their fanaticsm. So if we could associates out products with something that have a fanatics customer (let say sports team, music player, etc) then we could get instant promotions there…there is money there J in a way that we don’t even ever think before.