Yahoo! shares were pounded in a turbulent stock market despite its report that third-quarter sales were up 90%, to $295.5 million, over the year-ago period. Investors were concerned Yahoo! is vulnerable to advertising cutbacks by dot-com companies. Yahoo! executives told analysts only 40% of its advertising clients can now be described as "pure-play" Internet companies and only 10% could be described as in "financially questionable" condition. In trading Friday, Yahoo! closed at $60.00, off 26.15% for the week.