It's not all over between Microsoft and Yahoo! despite the former very publicly announcing walking away from the deal that refused to be.

Here's why? Yahoo! shareholder and billionaire investor Carl Icahn has threatened to lead a shareholder mutiny of sorts to oust Yahoo! Chief Executive Jerry Yang and the rest of the Yahoo! Board unless they pursuade Microsoft to revive its last offer of $47.5 billion. Icahn has notified Yahoo! that unless its Board renews negotiations with Microsoft, that fell apart May 3 after both sides did not agree on a price, Yang and company would be effectively jettisoned out of Yahoo!.

In a reply to Icahn, Yahoo! Chairman Roy Bostock has suggested that the company is geared to battle the activist shareholder. Bostock has criticized Icahn for harboring a 'significant misunderstanding of facts' about Microsoft's offer and about the Yahoo! Board's response. Bostock has stressed that Yahoo! remains open to a sale "if it (sale) offers their stockholders full and certain value".

Meanwhile, Icahn is kind of ready with an alternate Board of Directors to oust the existing Board in an election scheduled to take place on July 3 at Yahoo!'s annual meeting. If Icahn and team are successful, the new Board will fire Yang and company and renew negotiations with Microsoft. On a softer note, the investor has urged the existing Board to reopen talks saying a combination of Microsoft and Yahoo! would be the most sensible path for both companies. Bostock however maintains that Yang and team have the independence, knowledge, and commitment to navigate Yahoo! through the rapidly changing Internet environment, and deliver value for Yahoo! and its stockholders.

All said, Icahn may have breathed life into a deal well dead but it remains to be seen whether Microsoft is still interested in buying Yahoo! As a spokesperson for Microsoft remarked, the company has "moved on".