Yahoo! (YHOO) was up 13.7% in afternoon trading after Henry Blodget of Merrill Lynch applauded the Internet media company's decision to charge listing fees for its auctions. In a research note, Blodget said the move diversifies Yahoo!'s revenue stream and could contribute 3% to 5% of the company's revenue this year. In another note, U.S. Bancorp Piper Jaffray reiterated its buy rating and said the new fees could add 5 cents a share to Yahoo!'s earnings.