Yahoo has officially announced the end of talks with Microsoft:
Yahoo! Inc. - Press Release
With respect to an acquisition of Yahoo!'s search business alone that Microsoft had proposed, Yahoo!'s Board of Directors has determined, after careful evaluation, that such a transaction would not be consistent with the company's view of the converging search and display marketplaces, would leave the company without an independent search business that it views as critical to its strategic future and would not be in the best interests of Yahoo! stockholders.
Yahoo! Inc. - Press Release