Bad news from Silicon Valley: Yahoo posted a 78 percent drop in profit in the past quarter as advertisers cut back or went elsewhere. Display ads, typically from major brands like car companies, fell 13 percent in the quarter, and search ad revenue also dropped. The company is considering a search-advertising partnership with Microsoft that would pool their search ad assets and enable Microsoft to sell search ads on Yahoo pages. New CEO Carol Bartz said Yahoo would soon eliminate about 5 percent of its workforce, or about 675 positions. The company laid off 1,000 employees in the first quarter of 2008, and 1,500 more in December.