I keep forgetting that new display arm allows for that (rotation). Years ago I worked at a place and I had a monitor (was it ViewSonic?) that I could do this to. I was doing a lot of page layout/typesetting and it sometimes came in handy to just to see a long, vertical run of stuff. I didn't do it a lot, but it was a neat way to work once in a while, when it made sense.
I bet within 5-7 years, that feature will make its way down to all iMacs. Well, that's assuming the iMac even exists at that point. Apple might be out of the Mac/computer business - and there could be a 22" iPhone - by then.
