Yahoo Inc.'s third-quarter profit slid 38 percent amid slowing revenue growth that has raised investor doubts about the Internet bellwether's strategy and execution.

The Sunnyvale-based company said Tuesday that it earned $158.5 million, or 11 cents per share, for the three months ended in September. That compared with net income of $253.8 million, or 17 cents per share, in the same period last year.

The results matched analyst expectations, according to Thomson Financial.

The quarters weren't totally comparable because of new accounting rules requiring Yahoo to deduct the cost of employee stock options from this year's profit.

Revenue for this year's quarter totaled $1.58 billion, a 19 percent increase from $1.33 billion last year.

After subtracting commissions Yahoo paid its advertising partners, the third-quarter revenue fell to $1.12 billion. That figure missed analyst expectations that had been lowered by Yahoo management a month ago.

"While we are tremendously excited about many things happening at Yahoo, we are not satisfied with our third quarter financial performance," Yahoo Chairman Terry Semel.

Investors have been disappointed with Yahoo for most of this year, largely because the company hasn't been targeting online ads as effectively as Google Inc., the Internet search leader that runs the Web's largest marketing network.

Although it continues to run the most trafficked Web site on the Internet, Yahoo is facing a stiffer challenge from recent upstarts like MySpace.com, Facebook.com and YouTube.com, which Google is in the process of buying for $1.65 billion.

The problems have battered Yahoo's stock price, which has dropped by 38 percent this year. Yahoo shares dipped 3 cents Tuesday to close at $25.15 on the Nasdaq Stock Market, then regained 45 cents, or 2 percent, in extended trading.