Truth to say, I thoroughly enjoyed Prabhakar Raghavan's talk at the Leela. The talk started off with some facts about what and how users search on the web; delved into the complexities of understanding and deducing the users' needs; and few details on how the monetisation engine has proceeded over the years. The insights offered were quite delightful. The videos of the talk are available on the BigThinkers events page.

And, oh yeah! The video of the QA session is also available. :-)