Nothing really new here for folks that have read PG's essays. Could be valuable for those who haven't. Appreciate links to specific questions.
shameless brag - I've developed a chrome extension that creates immediate summaries from long video talks - Brieftube.com.
I used it myself on this talk and found the major topics in a few seconds.
Interesting. Is it automated, or is there some sort of human intervention in creating the summaries?