The U.S. Justice Department has agreed to share documents with California attorney general Jerry Brown's office regarding a possible antitrust suit against Google. Both federal and state lawyers are targeting Google over its deal to sell some of Yahoo's search ads. California's investigation comes at the behest of state assemblyman Joel Anderson, who wrote in a letter to Brown's office: "We're talking about giving (Google and Yahoo) over 90 percent market share — nobody else on the Web has a database like that. Who can compete?" If Anderson's concern sounds familiar, its because in recent days big advertisers, small advertisers and federal lawyers have expressed similar concerns with similar wording. That's because it's all coming from the same source: Microsoft and its CEO Steve Ballmer, who's still bitter about Google blocking its Yahoo acquisition. Says one trade reporter also subject to the Seattle company's lobbying efforts: