This marks the second time in four years that Yahoo has faced a boardroom challenge from a disgruntled shareholder. In 2008, billionaire Carl Icahn sought to overthrow Yahoo's board after the company balked at a chance to sell itself to Microsoft Corp. for $47.5 billion, or $33 per share. Icahn wound up accepting a truce that gave him and two of his hand-picked choices seats on Yahoo's board. Icahn and his allies are no longer on the board.