This month, GLEAM [= gay and lesbian employees at Microsoft, the GLBT employee group at MS] printed up a bunch of T-shirts, posters, and stickers:
I suppose they look lovely, but I'd be deeply ashamed to wear anything with that image on it, and it has nothing to do with homosexuality. It has everything to do with the missing serial comma.
Whenever you have a long list of things in a sentence, such as egg salad, ham and cheese, turkey, and roast beef sandwiches, you stick commas in there to separate each member from the others. If the final two items in the list are separate members, such as bisexual and transgender employees, then you stick a comma in there as well to indicate this. If, however, they are a single entity [e.g. "ham and cheese"], then you don't use a comma.
Given that there are plenty of bisexual (and a handful of transgender) MS employees, but no bisexual and transgender employees that I'm aware of, I would of course expect a comma before the 'and' on the posters, T-shirts, etc.
As a result, when I see those posters, the first thing that comes to mind is that whoever thought 'em up can't write English worth a damn, and this is embarassing. Of course, it doesn't seem to bother anyone else, though. Ah well.