In an effort to compete against Google (NSDQ: GOOG) and hoping other developers can help it get some search mojo back, Yahoo will let developers, general users (and even rivals) build customized search services on top of its core engine. The new service is called “Build Your Own Search,” or BOSS. Besides search, Yahoo (NSDQ: YHOO) is also unlocking its image and news databases to let outsiders create their own permutations of Yahoo News, or Flickr. Yahoo would even supply spell-checking services to partners.

Last month Yahoo signed a deal with its rival Google to run ad across some of its searches…this is another major effort to help the company gain share, any share, in the search market, and make developer fall in love with a company that has lost any kind of goodwill in Silicon Valley. More details here.