Yahoo already has content and search properties. They would do well to focus laser-sharp on how to properly monetize them.
You can speak to any advertiser who has used both Yahoo's and Google's ad management systems. Yahoo's is awkward and unreliable to the point of uselessness and many advertisers have completely abandoned Yahoo until that company gets purchased by someone who knows how to do the job right.
We're not asking much, Yahoo: Just provide an ad-management system which is as good as Google's was five years ago.
I just spent my afternoon adding a boatload of targeted search advertising to Google for a new campaign. I'd would have happily shoveled some of that cash Yahoo's way, but it would be a complete waste of time and money to do that today.