tedster - 6:12 pm on May 6, 2010 (gmt 0)
pontifex: maybe - Google is recognizing the keyword by search queries amount and applies less/more filtering or a completly different algo!
I'm pretty certain this is in place - and has been to a lesser degree for quite a while. Starting in 2009 Google engineers made a lot of comments about "user intention" and mentioned the three basic taxonomies for query terms: navigational, informational, transactional.
They also filed a patent about automatically generating taxonomies for query terms - so I'm pretty sure that the categories in use today are more granular than just those three top-level ones.
Query term taxonomy is a topic for a separate thread, and I'll try to start one soon. I think, as pontifex does, that it could be a significant part of the present shifts.