In an invitation email I want to know why I, rather than some other expert, would be an important addition to the conference.
At the first conference I talked at I wasn’t really welcomed. I just went to the room where I talked (which was very small, they could have told me) and set up my own laptop and didn’t know if I was doing the right thing. The talk went terrible because it made me even more nervous.
The conference organizers did not tell me upfront that I am not able to use my laptop on stage and my material needs to be passed to the A/V crew. As it turned out the AV crew expected a ppt presentation file which I could not provide since I use a html5 presentation kit. “Fixing” these kinds of issues right before hitting the stage sucks.
I hate draconian speaker contracts that make me personally liable if i can’t attend; I can’t sign a contract that binds my employer, and why would i risk my house when I get no personal benefit from speaking (because i don’t accept speaker fees; it’s my salaried job).
I dislike being told late that slides are 16:9 resolution/ must be CC-licensed, as I write my decks early.
Finding out at the last minute that my talk slot is longer (or shorter) than I’d expected is frustrating & difficult.
I run workshops, and give conference folk a list of needed materials. There have been a couple of occasions where things would have fouled up completely without the emergency stash of post-it notes and sharpies I always have with me.