I may be behind the curve (as I often am) but I hadn’t seen this used at a news site before: as I scrolled over the headlines at MacBytes.com this morning, I got a popup box with a short description of the article. I got a lot more information out of the site than I usually do, without having to click and follow the links.
It seems to me this would be a pretty valuable addition to those lists of headlines on media sites although there is a downside: if I can read the lede, the media company potentially loses the clickthrough to the inside pages, and therefore sets of eyeballs for the advertising.
One huge upside, of course, is that using such popups would put a premium on good lede-writing.
(Note: The image above is linked to a QuickTime screencast — about 250kb — showing the popups in action. It’s too small to easily read, but you’ll get the idea.)

