Andrei Broder from Yahoo Research gave the keynote talk, "From query based Information Retrieval to context driven Information Supply" (PDF), at the Future of Web Search Workshop.
I particularly like how Andrei describes some of the features of the current, "third generation" of web search engines as advancing over the previous generating by focusing on the "need behind the query." Examples include the Yahoo Shortcuts that appear on a search for [Britney Spears] and the inlined local results for a search for [dentists bronx].
Andrei then goes on to describe a future "fourth generation" of web search where search engines will no longer require explicit queries, but do "active information supply driven by user activity and context". As examples, he gives Yahoo Alerts and Amazon.com personalization and recommendations. He also says advertising will stop being irrelevant and annoying and start focusing on supplying interesting and relevant information targeted to each person's needs.
[via Gary Price]