Unless I'm doing something routine like downloading rules about when to use quotation marks, when I'm in front of a classroom, I often don't focus on the point I want to make; instead, I'm focused on getting someone in the class to articulate the point I've been dancing around; or, I improvise based on what the students are saying, in order to draw them out further. That's a very different activity than standing in the front of the room and delivering knowledge to a group of peers. It's generally obvious when I'm tanking in the classroom, because the students stop contributing. It's much harder to read an audience at a conference, and since you've written your speech out in advance, it's harder to adjust even if you are perceptive enough to pick up on the cues. At any rate, I'm much more experienced at trying to lead my students in an intellectual dance than I am at performing solo in front of trained experts.

I have seen presentations where the use of PowerPoint did not detract from the presentation. That's about the best I can say.

I think the worst symptom of PowerPoint abuse is "send out the deck" syndrome. Presenters use PowerPoint as a substitute for lecture notes instead of an audience-directed presentation tool, and the best evidence of this is that reading the deck is often a good substitute for (or even an improvement on) attending the lecture. People don't take notes during lectures if they think they can get the deck afterwards, which means they're even less involved with the lecture.

One of my professors this semester used an interesting device (more suited to a classroom than a non-interactive presentation) of using the projector to show an MS Word document containing the highest level outline of the material he was planning to cover (just three or four bullet points, no sub-topics), and filled it in as he went. It let him take responses from the class, plug them into his outline, then refine them until they matched what he intended to say.

Thanks, Kodi! Good points. I know exactly what you mean, too. Whenever I've received printouts of the lecture notes, it makes me want the presenter to do more "live" work since I don't need to put my attention into taking notes any longer. So it gets kind of infuriating to watch someone who just reads the notes I already have been given! I like that technique you mentioned -- designing the notes "live" on the screen. That sounds really useful (lord knows my classes have gone off topic in a productive way and I was left alone afterward, wishing I had a copy of the notes that the class had!)

And Dennis, I love the way put that: "leading students in an intellectual dance." That's really true for performative, interactive teachers. But I'm sure you'd agree that sometimes it's a rote square dance, and at its best a ballroom swing...but sometimes it's just a real mosh pit. Some students absolutely need dancing lessons, too...but I won't keep straining your apt and persuasive metaphor! ;-)

A ballroom dancer who is skilled at leading can make an inexperienced partner look, move, and feel great.

But now I'm looking this mixed workhorse of a metaphor in the mouth with a dead stick in the mud in your eye of a needle in a haystack.