There is a new feature in Office 2010 that I can't wait to try. It is called Broadcast Slideshow and it allows you to create a link to your presentation so others can watch it via the Internet. Brent Whichel of Office.411.com explains the feature in this video.
I think of the number of times we set up webinars to share information. From my understanding, this feature can replace a basic webinar. Just create and distribute a link to your PowerPoint presentation and others can follow along in a web browser as you flip through your slides. Now, granted, there are polling and other features that webinars offer, but this is a simple alternative when you just want to share a presentation.
When I am working on developing a presentation with a client, I often find that we are each going through the same presentation slide-by-slide discussing what needs to be changed. That requires the repetitive dialogue of 'now we are on slide x'. With the Broadcast Slideshow feature, that dialogue will not be needed because as I flip to a new slide, my client will be able to see that same slide.
Of course, being a Mac user, I will have to wait until 2011 before I can get the full-powered version.