Conference blogging is what I suggested actually. I would have liked to read the summaries of talks, the reactions, the comments of the participants on their blogs. If you search for blogs on mkm2007 all you find are the posts of P. R. Rust, a chemist. This kind of blogging has not caught up with mathematicians. As for the best format for math on the web, I am biased in my preference that is easily guessed. On the other hand, I would like to point out that flash is heavily used also (and can be generated quite conveniently from PDF).