They talk about how the engine works, and what they're doing to beat the competition. Watch me give them a bit of heck about being behind the other major engines.
*For those of you who are web search "historians," Selberg was one of the original developers (with Oren Etzioni) of MetaCrawler at the University of Washington about 10 years ago. More about MetaCrawler here.
Postscript: On a somewhat unrelated note, I noticed that Microsoft's Web Search and Data Mining team in Silicon Valley now has a web page. It lists several of their projects along with lots of papers to read. More? Here are the pages for similar teams in Redmond and Asia.