I've been following the career arch of corporate raider Carl Icahn for years. The billionaire investor specializes in buying up huge chunks of stocks of volatile companies, then going after the company's board of directors to get the deals he wants.

It's worked pretty well with Icahn's investments in companies like TWA, Motorola, an Time-Warner over the years. Icahn hasn't made as many corporate board members walk the plank as he'd like, but he's made a ton of money as maybe the world's most famous "activist shareholder".

Now, it looks like Icahn has set his scope on Yahoo. After CEO Jerry Yang turned his back on an offer from Microsoft to buy the company, scores of Yahoo shareholders have balked - but none have the bite of Icahn. In the past few weeks, Icahn has been buying up millions of shares of Yahoo stock, hoping to buy some leverage and get the company to reopen negotiations with Microsoft. If that happens, and Microsoft comes back to the table with an offer of, say, $32 per share, then Icahn makes a boatload of money buying in at less than $30 a share (the stock is currently trading at around $27 per share), especially since Yahoo's stock is sure to rise significantly if a deal is struck.

The Icahn template here is a familiar one. Get the board fired - or, at least selected members - and find new board members who'll dance to his tune and push for a deal with Microsoft, if not Google. But his track record in replacing board members is a lousy one (he made hundreds of millions on the Motorola and Time-Warner plays, but didn't get the boards to flip like he wanted). Also, this time Icahn doesn't have other big Yahoo shareholders on board with him.

Plus, Yahoo's own deadlines are working against him. This Thursday’s deadline is fast approaching for interested parties to nominate an alternate slate to Yahoo’s board.
Icahn, who has reportedly purchased 50 million shares of Yahoo, or 3.5% of the company, since the Microsoft deal fell apart, doesn't have a lot of wiggle room here. The word on Wall Street is that Icahn’s immediate goal is to get Microsoft back to the table. Meanwhile, Icahn has 24 hours to reveal whether he’s going to put up an alternate slate.

That's a lot of work in a short period of time - even for a seasoned buccaneer like Carl Icahn.