These are exciting times for Microsoft (NASDAQ:MSFT), as its portal nears the public launch of its paid search service. With Google (NASDAQ:GOOG) and Yahoo! (NASDAQ:YHOO) running away with the booming targeted text-based ad market, the beta version of MSN's AdCenter has taken some major strides over the past few days.

Microsoft's popular portal has been selectively inviting advertisers into its pilot program for months now, but recently it's been willing to take on a little extra weight. On Thursday and Friday of last week, Microsoft opened up the signups to the general public. The open house lasted all of 48 hours, but MSN is ready to absorb even more sponsors now. Yesterday, it sent out a letter to its pilot members that allowed them to invite another 10 new advertisers apiece.

None of this guarantees that MSN will make a sizeable dent in this market. MSN was initially promoting the ability for advertisers to target specific demographics -- beyond regional campaigns -- but lately, Google has also been ramping up that ability as well.

Microsoft has come a long way. Just a couple of years ago, the company was outsourcing its virtual real estate to smaller providers like LookSmart (NASDAQ:LOOK). However, a lot is at stake here. Google is a company that derives 99% of its revenues from online advertising, and it's valued as a $110 billion company. Microsoft would be tickled if its online arm could reach that kind of valuation, given that is consistently topping Google in terms of traffic.

A successful launch would naturally provide a boost to Microsoft's shares. The stock has been stuck in the $20s for ages. That isn't necessarily a bad thing; it's allowed value investors like Philip Durell to latch on to a quality software giant like Mr. Softy at a historically attractive price. Philip recommended the shares to Inside Value newsletter subscribers five months ago, and the stock has since climbed 11%.

After souring investors by delaying the launch of its Vista operating system, Microsoft is seeking growth from some unlikely sources -- like its Xbox 360 video game system and its AdCenter paid search product -- to reignite investor interest. Yes, the world's largest software company has some intriguing revenue streams worth paddling these days. Let's hope that the company doesn't leave its shareholders up the creek.

Come back tomorrow, when Chuck Saletta and Tim Beyers tackle the pros and cons of Mr. Softy in our weekly Dueling Fools segment. Until then, you can check out the other stocks that Philip finds trading at compelling values by checking out a free 30-day trial subscription to Inside Value.

Longtime Fool contributor Rick Munarriz likes what he has seen out of the AdCenter beta, though the reporting interface is still pretty clunky compared to its larger rivals. He does not own shares in any of the companies in this story. The Fool has a disclosure policy. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.