First things first 24fps is the fps used by film/movies. Real film can be shot at a low 24fps because each frame can be motion blurred by having long exposures so that each frame will be seamless into the next. Long exposures takes an insane amount of processing power. To do it right you would need to process something like 24 images shot with 1/25s exposures every second. Looking at samples, on Nikon's website, they are ok, but it still looks like a movie with low fps. In other words, more choppy than cinematic. It is no mistake why they chose more slow moving objects, than say someone briskly walking with arms swinging back and fourth.
A good assumption to would be fair make about users who think video is the next breakthrough in dSLR technology is that they probably don't own a dSLR. Taking pictures with a highly specialized (and expensive tool) was never something they were completely sold on, which is why they don't own one. They might have been on the boarderline of buying a dSLR, but after the video feature was added to the D90, it was the feature that pushed them over the edge. So kudos to Nikon for making it happen.
So today, in the dpreview forums, there was a massive amount of people who were more than in-your-face about the fact that they have finally not chosen Canon in the Canon forums because Nikon made the right move. Is there any point to arguing with a person who wants to buy a highly specialized photography tool with a plan to shoot video? Especially when better video equipment has been around forever. These people are neither photographers or videographers. They are just proud that they've finally made up their mind whether to go with Nikon or Canon.
Seriously, when is the last time you picked up your dSLR and thought "damn, I wish this thing had video?" It just doesn't click.
The phenomena itself wasn't the camera, but the barrage of soon to be first time dSLR owners who all collectively made up their mind that D90 has the extra something they have been waiting to jump on when it comes out. If a Canon one day comes with video, maybe I'll use it once in a blue moon because its there, but I really can't see someone who has photography in their mind giving any weight to the video feature.
Update: After reading the D90 reviews, I take back a lot of things I said about the camera. The video indeed does suck, but the camera itself is awesome, more so than anything Canon has announced recently. Nikon is still in the photography business, Canon seems to be changing their focus so that their features are more appealing to the everyday consumer which is ultimately going to be disadvantageous image quality. Please Canon, no more megapixels. 15 is too much for the APS-C, and I can't imagine what a pain a 21 megapixel raw file will be to handle.