If you come across an article from News.Com http://news.com.com/2100-1024_3-1027084.html

(about Yahoo/Overture) mentions Google. PageRank to be specific. The article says that Google has a patent on PageRank. That's incorrect. The PageRank patent is in the control of Stanford University not Google Inc.

Btw, this site has a list of Yahoo patents and an even more interesting list of some Microsoft search patents. Perhaps a clue to what they are up to.