Flickr photo pages switched to Ajax (from Flash)
The photo pages on Flickr now use DHTML/Ajax to display images and notes. See the this Flickr weblog post. Photos were previously displayed using (an admittedly well-done) Flash app.
Given the recent fervor around Ajax, libraries making cross-browser scripting easier, and very nice implementations on sites like Backpack and now Flickr, I can’t help but believe this is a trend that will gain momentum quickly.