What is the key difference between Yahoo and Google?
Well, one difference is that Yahoo wants to offer Content primarily and offer search as a tool to findout the content. Google wants to offer Search as a primary tool to find that content.
While Yahoo builds content sites and offer them to readers, Google is only building toolsets to create such content by individual users.
Which is more powerful? Creating content or building a toolset to let users create the content and help them find it? I guess, the later. So Google will be clear winner even in terms of content.