My boss and co-workers were complaining that GMail does not allow you to turn off "conversation view", where items with the same subject are grouped together. I found it within a few minutes, and a quick test confirmed that it works just as described. It's a pretty recent addition, though, so it's no wonder they didn't know it existed. What I don't understand is why you wouldn't want it. Personally, I would hate to be searching through my email looking for the different connected pieces of one conversation. I suppose if you get tons of unrelated mail all with the same subject heading it might get annoying, but apart from that, I'd rather have it on than off.
Mokalus of Borg
PS - I don't get a lot of same-subject email.
PPS - And GMail doesn't seem to group it together anyway if there's a long gap.