The suggestion is that iMovie and the iWork applications (Pages, Keynote and Numbers) will be offered either in web-based versions or with much greater integration between the desktop apps and Apple's web-based services.
The idea of using an online video editor has some attractions, but the downside is the time it would take to upload the raw footage. For example, a 6.5 minute video clip in DV format takes occupies around 1.3G of storage space. And given the asymmetric nature of most domestic Internet connections, you're not going to upload that in a few minutes.
Integrating desktop and web applications would allow the footage to be transcoded into a more compact format before it is uploaded. Fine for stuff you plan to share on the web, but not so good if you want DVD quality.
On the other hand, being able to deliver Keynote presentations or share Pages or Numbers documents over the web would have many advantages, especially if the other people were not using a Mac.
Apple has been doing a lot of work to allow web applications to deliver a desktop-style experience, and it seems unlikely that effort would only be used for web mail.