Lol football is very interesting comparison because it's such a different field of interest, yet so similar a fodder for fannish behaviour. How comparable is it? What do you have to say abouut people's discourses and attitudes about this?

Well, the great majority of people are fannish by simply watching/reading and discussing a little bit between friends. But some people like to do something more interpretative, creative, systematic or participative. That's where you get fanfics, fanarts, filks, RPGs, collections, etc. from. All of it is fandom, just different kind of, IMO.

I think your point about teenage is very well taken and important, especially about the fangirl/boy as stereotypes. Both are caracterized as immature in many ways.