Maish Nichani and Venkat Rajamanickam have examined a number of interactive presentations, including a few on news sites, and come up with a simple classification scheme.
Looks like a promising start, might be worth comparing with Nora Paul's attempts to come up with the "elements of interaction". Also, I might add a "comparative" category, that works through contrast and comparison, especially of images.
Thanks to the WebWord.com Weblog