I built a search engine for talks (http://findlectures.com/), and one of the explicit goals was not to collect user data for privacy.

The content is selected by recommendations - e.g. someone on HN say a speaker was good, so bring in all the conferences they spoke at, then there are some filters to exclude things (e.g. terrible audio).

There are also facets to explore different ways, and my experience has been that this approach works well for researching new technology, in that I can typically find a small number of highly relevant talks on a subject I'm researching.