Now comes the interesting part for Yahoo.

With the takeover premium supplied by Microsoft officially gone from Yahoo's stock price, everyone will now get a look at what the company is worth by itself.

Today the markets are valuing Yahoo at just under $28 billion, or about 50% less than what Microsoft was willing to pay.

As I've written before, Yahoo won't survive in its current form because it suffers from a wide disconnect between its cost structure, its strategy and its competitive landscape.

Here's another way of saying it. The company employs thousands of people in its many units that provide content. But while many of those channels, such as its Money, Sports and Technology, are tops in their online categories, their revenue growth has slowed as more advertisers turn away from static branded ads.

The bulk of Yahoo's growth -- and cash flow -- still comes from its search advertising unit. The problem there is that bigger rival Google has been taking market share for years.

The market share bites may be little -- a percent one quarter or half a percent in another -- but they've  added up over time to where Google now serves up two out of every three search queries. Yahoo's share is about one in five.

Thanks to their recent partnership agreement that will outsource some of Yahoo's search business to Google, Yahoo will be able to boost its cash flow. This confirms what observers have long seen: after several years and billions of dollars in development costs, Yahoo's search is significantly inferior to Google's in generating relevant ads.

On top of all this, Yahoo continues to bleed top talent like a ruptured artery. Stemming the flow and trying to replace key staff losses only adds to the distractions for CEO Jerry Yang, who's already got a full plate, what with Carl Icahn's proxy fight and the shareholder lawsuits and all.  

Yahoo's shares may continue to fall on their own as investors wait to see if Icahn can unseat the company's board. But if the market for tech stocks continues to head south, Yahoo's slide may become so precipitous that other suitors besides Microsoft start to become interested.

I'd written earlier that it may take a year or two to see Yahoo either split up or sold off once Microsoft walked away. But given how fast Wall Street is discounting its worth, the end of Yahoo as we know it could come even earlier.