You know, there's apparently more to Microsoft's (NASDAQ:MSFT) new Bing search engine than just the novelty of something fresh.

According to market research firm comScore (NASDAQ:SCOR), Bing continues to grow its audience.

If so, that's a rare online win for Microsoft -- and an important one. Everyone figured that Bing would draw a crowd initially. Media headlines and an aggressive marketing campaign virtually assured a big opening push. However, to see Bing gaining ground over the past two weeks since its inception is a huge deal. Folks aren't just trying Bing. They're sticking around and telling their friends.

Metric

5/25-5/29

6/1-6/5

6/8-6/12

Search Penetration

13.7%

15.8%

16.7%

Search Results Share

9.1%

11.3%

12.1%

Source: comScore qSearch.

If the improving trend isn't making folks nervous at Google (NASDAQ:GOOG) -- and perhaps more importantly, Yahoo! (NASDAQ:YHOO) -- it should.

Everyone seems to be looking at Bing's impact on Google, and understandably so. Big G relies on Internet advertising to bring home the bacon, and there might not be as much sizzle in the pan if Bing is taking market share at Google's expense.

But Yahoo! has to be the real worrywart. If Bing is able to keep up its current pace, Yahoo! will have to take its silver medal in search and trade it in for a bronze. The last thing Yahoo! needs is fading relevance among its advertisers.

Bing's success will also make it less likely that Microsoft pursues the acquisition of Yahoo!'s search business. A partnership is always possible, but suddenly Microsoft has a little more leverage. Now Yahoo! may decide to start eyeing smaller search engines, such as IAC's (NASDAQ:IACI) Ask.com, or it could try to team up with Time Warner's (NYSE:TWX) AOL.

The market still hasn't entirely forgiven Yahoo! for losing ground to Google. It's not going to be pretty if Yahoo! lets Microsoft speed by as well.

If the "start wearing purple" people at Yahoo! aren't seeing red now, they may have to settle for a shade of envious green.

The world according to Microsoft:

Google is a Motley Fool Rule Breakers selection. Microsoft is a Motley Fool Inside Value recommendation. Try any of our Foolish newsletter services free for 30 days.

Longtime Fool contributor Rick Munarriz admits it: He has turned to Bing a lot over the past two weeks. Rick owns no shares in any of the stocks in this story and is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.