Jakob Nielsen has an interesting Alertbox column entitled Information Foraging: Why Google Makes People Leave Your Site Faster.

The easier it is to find places with good information, the less time users will spend visiting any individual website. This is one of many conclusions that follow from analyzing how people optimize their behavior in online information systems.

This argument makes a lot of intuitive sense. I've personally been going to Google News a lot more to look for news stories and as a consequence do not go to the front pages of news sites as often as I used to.

Search engines still have a long way to go though. In some topic areas the sales sites for particular products will dominate over technical discussions of the performance of products. In other topic areas amateur sites with little useful knowledge will show up high in a search result list while pages with the most insightful analyses get low ranking.

One feature I'd like to see Google support is a date-sorted return in regular pages like it does on news pages. Sometimes one is looking for the latest that has been said on a topic and while one can restrict Google searches to recent months in the Advanced Search facility it is not the same thing. What would be nice would be more knobs to turn to tell Google the kind of page one is looking for. Rather than simply sort by date it would be nice to just say "assign more weight to page date in the index algorithm" or "assign more weight to academic papers in the index algorithm".