I'm a little surprised that Yahoo! (YHOO) stock is jumping more than $1 today after it reported fourth quarter numbers last night. If you look at the company's 2007 guidance, most metrics are below current consensus forecasts. Revenue growth for the fourth quarter was 15% and 2007 growth will fall between 9% and 20%, according to the company. Yahoo! hardly appears to be a high growth Internet leader anymore.

That said, the stock is rallying as investors hope that an early release of their new ad system, Panama, will boost the bottom line of their network's online advertisements. Without actual evidence that Panama will boost Yahoo!'s ad margins (the program launches in February) and help it regain market share lost to Google (GOOG), I'd be cautious going forward. If Panama stops the bleeding, YHOO shares will likely trade well into the thirties, but if the platform's bark is stronger than its bite, investors might be let down.

Full Disclosure: Long GOOG and short YHOO at time of writing