In the states, I have a large handful of friends who support Chelsea and ManU, then one each for: The RS, Spurs, Blackburn, Newcastle and Fulham.
The fans of the latter four have at least some kind of reason for following the team. The Reds supporter lived in L'pool for three years, and they got to him first.
As for the friends I have who are "supporters" of the rest, well, you can just tell they root for front runners.
As for Everton, every time I talk with someone about football, they always make a point to tell me I'm the "only Evertone fan I've ever met." When I ask what they know of the club, the answer is always the same ... they say Everton's a good team, but they don't know anything else other than that. One guy actually knew we'd just beaten Liverpool in the FA cup. But that's about it.