Microsoft needs to concentrate on a different kind of search: finding a buyer for Bing, its online search business. Bing is the industry’s distant No. 2 after Google. It has become a distraction for the software giant — one that costs shareholders dearly. The division that houses Bing lost $2.6 billion in the latest fiscal year. Facebook, or even Apple, might make a better home for Bing. A sale would be a boon for Microsoft’s investors.