280 Slides Site translates Objective-C to Javascript

Well, for one, 280 Slides is free. PowerPoint is far from it. More importantly, its really nice to use software that you don't have to install or download, and that gets automatically updated to the newest version. Plus, neither PowerPoint or Keynote lets you search the web for media directly.

Web apps are compelling for the same reasons that make web-based email so incredibly popular: no download/install process, and access to your data from any internet-connected computer.

Exactly. I'm being downmodded for my comment, but there's no real benefit to this but a lot of downsides. I can't control it with a remote. I can't easily run it full-screen. I can't easily add the types of high quality movies and pictures I'd expect presentations of mine to have. And to hell with export to PowerPoint. One, even if export is truly 1:1 with the original work (which I doubt, exports area always quirky at some level) I'd still need to jump into another program to do the presentation. Rather than downmodding comments like mine and yours, maybe they should actually chat with people that do presentations for a living instead of running with a "wouldn't it be cool if [fill in application] was made into a web app" train of thought like they seem to have. As I said, the programming looks very well done, I'm not mocking that aspect of this. But there are just far too many limitations to this.

So enough armchair critiquing, here's what might help this. Add export presentation functionality to Flash or QuickTime. Seriously. Both formats are relatively cross-platform, and would mean I could use a standalone player to launch the presentation full screen and not have to rely on Keynote/PowerPoint. Secondly, I know it's 2008 and we have Internet access via cellphone and wifi. But don't assume presenters will have access to a reliable, fast, connection. Maybe in 2015 I'll look back at my comment and laugh because fast wireless Internet access is near ubiquitous everywhere and my criticisms no longer apply. But my criticisms are born out of a sense of pragmatism. Never have I gone into a presentation assuming Internet access would work. At almost every conference there's at least a couple of presenters that get caught out because a site is down, the Internet connection is flaky, or about 50 people in the audience are blogging and saturating the bandwidth until it is slow as molasses.