Once upon a time, Yahoo (YHOO) and Microsoft (MSFT) were on the verge of getting hitched. But their respective CEOs, Jerry Yang and Steve Ballmer, couldn’t seem to agree about money, and they were forced to call the whole thing off.

Microsoft, however, may come courting again, if Carl Icahn’s attempt to remove Yahoo’s board -- and CEO Yang in particular -- proves successful. The folks in Redmond aren’t the only ones poised to back Icahn: Capital Research Global Investors, which holds 6.5% of Yahoo’s shares, is “seriously considering” voting against Yahoo in the upcoming proxy fight.

News that Capital may be on his side will almost certainly embolden Icahn and move the well-known activist to push even harder for his slate of directors. There’s clearly blood in the water, and I trust that a shark like Icahn will be well able to smell it.

The fact that Microsoft has expressed willingness to resume takeover negotiations with a new board provides shareholders with tremendous incentive to vote for Icahn and his slate at Yahoo’s annual meeting on August 1st. The stock is in the doldrums, its current board is under fire and archrival Google (GOOG) is daily consolidating its position.

Frankly, I don’t see how Jerry Yang can hope to keep his job: He and his board still haven’t offered a well-defined turnaround plan, nor have they put forth an aggressive vision for the future.

And Yang's statements to Capital Research’s Gordon Crawford on July 1st scarcely strengthen his credibility. For example, Yang maintained that the decision to revamp Yahoo's management structure was sound - never mind that it caused massive upheaval and mistrust within the company.

Yang also called the many executives who have recently left Yahoo's sinking ship  -- including tech “rock star” Qi Lu, Yahoo Search’s Vish Makhijani, and Communications and Communities head Brad Garlinghouse -- “MBA types.” To dismiss such industry pathbreakers as a bunch of business-school dropouts is misleading, to say the least, particularly since Garlinghouse was the first to call for deep structural change at Yahoo over two years ago, with his famous (or infamous) “Peanut Butter Manifesto.”

With Icahn’s momentum building, Yahoo’s stock could start to tick up. How much remains to be seen, but I wouldn’t be surprised to see shares trading at $28 or $29.

Change seems to be in the air.

Yahoo closed at $23.91, up $2.56 or 11.99%.