Actually, you're the one who is lacking familiarity. The movie is doing well on a PER-THEATRE basis BECAUSE of the limited release. It only opened in theaters where it was expected to do well.
Top ten in under a 100 theaters equals very big deal. Almost never happens. But of course it's all guesswork at this point--let's have this conversation in a month. What can I say? In the industry I work in there are a lot of gay people. That I'm not one of them is beside the point. I have a different perspective on it--it frankly just doesn't seem to be that big a deal at all, and when you're working and hanging out with gay people, particularly when my wife and I go out to dinner or see movies with gay couples, the issue completely disappears faster than you can imagine. Just part of the fabric of life. And Brokeback Mountain is a work of art that your grandchildren will be watching.