I think you wrong to separate these things. I have sat through a pretty wide variety of presentations, from non-technical HR fluff no one cares about to deep te

I think you wrong to separate these things. I have sat through a pretty wide variety of presentations, from non-technical HR fluff no one cares about to deep technical designs involving correctness proofs etc. The main difference between the two is how many people are familiar enough with the topic to be able to get any value from the presentation at all. As far as the skills needed by the speaker to present the content effectively, it's almost exactly the same. Yes you need to understand the material yourself, but if you are boring and articulate poorly and don't understand how to relate the audience, it doesn't matter if you're presenting rocket designs or sales fluff. No one is going to remember it 20 minutes later.