Many presentations at conferences aren’t all that compelling. It would have worked equally well to read something about the subject in a book or on the web. But for some subjects there is no alternative to a video or even life presentation.
I recently stumbled over a recording of the talk Web Accessibility - a users perspective by Darren Fittler at the Webstock conference. Darren works as a lawyer and website accessibility consultant and he is blind. In this fascinating presentation the audience can see and hear what it is like to surf the web with a screen reader and how important good website design is to help visually impaired people. There are audio and video recordings in several formats available, see for yourself.
I have read through web accessibility guidelines before and tried to make my web pages not suck totally in that regard, but actually seeing how websites are browsed by blind people gives me a whole new perspective.