In the history of business, few competitors have been more deadly than Microsoft (NASDAQ:MSFT). Just ask Netscape. Or Apple (NASDAQ:AAPL). Or Borland (NASDAQ:BORL). Or ... well, you get the picture, right?

We've known for a while now that Google (NASDAQ:GOOG) has been in Mr. Softy's sights. We just didn't know exactly what the plan of attack would be. Last week, we got what may be a very important clue, when rumors surfaced of talks between Microsoft and Time Warner's (NYSE:TWX) AOL unit that could have Mr. Softy taking a sizeable stake in that popular online portal.

Conspiracy theories abound, of course. The one I find most intriguing says that Microsoft wants AOL to cut off Google's air. (The search king received 12% of its 2004 revenue, or $382 million, from AOL.) Naturally, such speculation demands a response. And it came yesterday, when cited a Merrill Lynch analyst in reporting that Google may make its own offer for AOL.

That makes sense to me. Google would get to keep prized real estate for ads and accelerate the creation of a portal comparable to MyYahoo! and MSN. (What else did you think Gmail, Froogle, and Google News were for, anyway?)

But I think there's something bigger going on. I think the spate of rumors suggests that Microsoft's campaign to damage Google has finally begun in earnest. Consider the series of recent events. Not even two months ago, CEO Steve Ballmer told financial analysts he was intent on seeing Microsoft be No. 1 in Internet services -- including search -- and Net advertising, according to Investor's Business Daily. That's as clear a sign as you'll get that Mr. Softy is getting hard-nosed.

There's been no formal response from Google that I've seen, but I'm hardly surprised to see the company raising $4.1 billion from new stock with Microsoft breathing down its neck. Wouldn't you want as much money in your war chest as you could muster if Microsoft and its $38 billion in cash came calling? I would.

Don't get me wrong: I don't think Microsoft is capable of killing Google. Not any longer. Google is too well-capitalized and too loaded with talent, and it boasts a very strong and well-defined market position. But a Microsoft-AOL deal would still be scary. That the mainstream press knows it marks the first time the so-called pundit set has admitted to -- let alone written about -- deep vulnerabilities in Google's thus-far impenetrable franchise. Shareholders beware.

You needn't search for related Foolishness. It's all right here:

Do you loathe the thought of pricey tech stocks? Do you go to the mall and shop only in the bargain aisle? Do garage sales actually appeal to you? If so, Motley Fool Inside Value was made for you. Learn how Philip Durell and our Foolish band of value investing analysts buy stocks on sale; take a risk-free trial today. Your portfolio will thank you.

Time Warner is a Motley Fool Stock Advisor recommendation.

Fool contributor Tim Beyers thinks Mr. Softy is as hard-nosed and passionate as they come in the business world. Don't believe him? Check out this exhortation (a video file) to Microsoft loyalists by CEO Steve Ballmer. Tim didn't own shares in any of the companies mentioned in this story at the time of publication. You can find out what's in his portfolio by checking Tim's Fool profile, which is here. The Motley Fool has an ironclad disclosure policy.