Google's traditional mission statement is to "organize the world's information." Yahoo has never been as much about organizing information as much as it is about finding information (original Yahoo portal), centralizing personal information (My Yahoo), and generating information.
Google has recently launched some pretty cool things. Even though I work for Yahoo, I don't hesitate to say it when Google launches good stuff. Good stuff is good stuff!
The world need both companies. Yahoo can generate the content and let Google organize it. ^^
Check out Google's latest toys and the new Yahoo! Homepage.