Yahoo!'s Shares Fall

Updated from 7:34 a.m. EDT

Yahoo! (YHOO) shares fell 2.4% early Wednesday as Wall Street hemmed and hawed over its reaction to the latest developments at the Net giant.

Shares rose earlier as investors sighed with relief at the company's promise to roll out a once-delayed search-technology upgrade overcame several pieces of bad news.

But the gains evaporated as trading continued Wednesday, as fans mused over how Yahoo! had missed its third-quarter revenue target, citing "unanticipated challenges." It also guided below the consensus estimate on its fourth-quarter top line.

The hard-hit media company also rolled out a $3 billion stock buyback and said on a conference call that its eagerly anticipated Project Panama upgrade is on track for rollout this winter.

Yahoo! shares recently fell 57 cents to $23.59 after earlier hitting a 52-week low of $23.38.

Terry Semel, Yahoo!'s CEO, said that the interface of Project Panama went live Tuesday, and that the company has brought its first external customer onto the new interface. Panama is intended to help Yahoo! compete with the bully on the Internet advertising block, Google (GOOG).

Semel said Yahoo! will maintain a "laser-like focus" on closing the gap on monetizing searches, widening its lead in graphical advertising, and continuing to build its presence in social media, video and mobile devices. He also said that the company counts 30 million users between the ages of 15 and 24 -- a tech-savvy demographic often coveted by advertisers.

The Sunnyvale, Calif., Net giant made $159 million, or 11 cents a share, for the quarter ended Sept. 30, down from the year-ago $254 million, or 17 cents a share.