Yahoo named on Monday a database guru to study links between computer and human-aided search.
Raghu Ramakrishnan, formerly professor of computer sciences at UW-Madison, is now at Yahoo Research helping the company define its social search strategy.
Yahoo sees social search as a major part of its strategy against Google. Google relies on computer-aided search, but does have some products -- such as Google Co-Op -- that rely on user expertise.
Yahoo has invested heavily in social search with the acquistion of social bookmarking site del.icio.us and photo sharing site Flickr, both of which use user-generated taxonomies to self-organize data. Yahoo has also developed a service called Yahoo Answers which matches user questions with user answers.
Yahoo's not the only one making competitive hiring moves. Microsoft recently advertised for a position called "Google compete lead" who will unite all Microsoft's Google compete iniatives.
Meanwhile, Google's been steadily poaching Microsoft employees.