I agree-looks mutually beneficial. Yahoo's strength hasn't been search for a long time and MS is trying to break into that market. Sounds like MS gets more traffic to search and Yahoo gets more traffic to sites where they actually have strength (e.g. yahoo finance, yahoo sports, etc).

If I've learned anything about MS over the years it's that they don't break new ground very well but they do a helluva job coming in after the fact and muscling their way up (eg Windows, Xbox, now search...)