Casual Dress
This distinction may be mostly 'meta' - useful to those who live, work, and report on gamer culture and community. Or maybe not. I don't have a good sense of how much Barbara Gamer worries these points. What is interesting, though, is that I heard once that this distinction might be more meaningful to those who only "casually play" than the other way around: John Average doesn't want to be associated with what his son does... This is an attitude (deeper than that, it's a disposition) which I'd suggest is rooted in developer practice generally, and computer games developer practice specifically.