Crusading, faux white knight Carl Icahn is at it again.

Icahn sent a letter to Yahoo board chairman Roy Bostock announcing that he is going to lead a proxy fight to try and oust the board members whom he said "botched" a deal with Microsoft.

If you're a Microsoft customer or use Yahoo products, you should be praying for his failure. Predators may pose as white knights, but predators don't kill their prey on behalf of their ecosystem; any resemblance between greed and benevolence is purely coincidental.

Joe Wilcox offers plenty of reasons why a merger between the two companies could be fatal to Microsoft and bad for Yahoo as well. But Icahn couldn't care less about that. And some Yahoo shareholders probably agree with him.

But that doesn't mean you should.

Icahn doesn't often lose his prey, but fortunately, he doesn't have a perfect track record either. He just doesn't brag about his failures.

This is far from Icahn's first crusade, and as usual, he's painting himself as an activist with the interests of his fellow stockholders at heart.

"During the past week, a number of shareholders have asked me to lead a proxy fight to attempt to remove the current board and to establish a new board which would attempt to negotiate a successful merger with Microsoft."

(Bashful Carl wouldn't have done this without their prodding. Right.)

Let's not forget, however, that Icahn was a pioneer of greenmail and junk bonds; fictional Wall Street financier Gordon Gekko, who uttered the famous but oft-misquoted line, "greed is, for lack of a better word, good," was modeled on Icahn and fellow junk bond dealer Ivan Boesky.

He has never been shy to throw his weight around, whether raiding RJ Nabisco and BF Goodrich in the 1970s and 80s, or threatening legal action and proxy fights against Motorola, BEA, and now Yahoo.

His tactics have changed, because the law no longer looks kindly on many of his previous antics, but he remains dangerous.

His primary motivation, of course, is money. That might seem like a good thing, especially if you're a Yahoo shareholder pining for $33 per share. But just focusing on the numbers doesn't always work, especially if the raider in question doesn't understand the business.

Icahn suffered a pretty humiliating lesson when he dabbled in biotech, but it looks like he failed to learn his lesson.

The IN VIVO blog noted:

"Investing in biotech isn't easy. It requires plenty of research; understanding products; contracts; the environment. The best investors in this industry know what they're talking about because they study hard to figure it out. But by and large, we haven't seen much evidence that the activists in biotech are doing their assigned homework."

His letter to Bostock contains hints at how far from informed he is.

His claim that "a combination between Yahoo and Microsoft would form a dynamic company and more importantly would be a force strong enough to compete with Google on the Internet," is dubious at best. It's clear that he hasn't thought about the major issues a combined MicroHoo would face.

I agree with Joe Wilcox and have also outlined why MicroHoo would be bad for customers of both companies.

I'd say he hasn't thought about them because he doesn't care. He'll grab the money and run, leaving MicroHoo customers holding a bag full of empty promises.