Microsoft is fed up with waiting, as Yahoo searches for alternatives to its offer…how will this story end? Yahoo is exploring new possibilities outside the Microsoft sphere, but everyone is wondering how solid can other alliances be in the current situation.

The latest name on everyone’s lips is Google, as Yahoo announced on Wednesday an agreement for conducting a limited test of Google’s AdSense for Search service. However, the question that emerges is: is such an alliance possible? Probably not…

Gartner analysts Van Baker told AFP: “The company that would clearly want to come to the rescue is Google but they know the regulators would just go nuclear if they did that,” as Google and Yahoo would therefore control 90 percent of the online search ad market.

Analysts’ predictions find Yahoo in a lost battle, struggling to escape an offer that it will most probably have to accept or better yet, trying to boost it, as the company considers the current offer to be insufficient.

Yahoo said in a letter to Microsoft: “We continue to believe that your proposal is not in the best interests of Yahoo and our stockholders […] Furthermore, as a result of the decrease in our own stock price, the value of your proposal today is significantly lower than it was when you made your initial proposal.”

Amongst viable alternatives for Yahoo, only one name comes out, and that is Microsoft, who really wants to put an end to Google’s dominance on online search ad market. But Google’s advantage on the market would be hard to surpass just with a Microsoft-Yahoo alliance, and this is where a third player might come in, as rumors on a possible Microsoft-News Corp agreement started to appear.

Microsoft gave an ultimatum to Yahoo in a letter sent on April 5, stating that if the two companies will not begin negotiations on a definitive agreement within the next three weeks, they will take the case directly to the shareholders and start a proxy contest to elect a slate of director for the Yahoo Board.

It seems there isn’t really a way out for Yahoo, as neither Google, nor Time Warner’s AOL would do the trick. In the meantime, Yahoo keeps up its game trying to raise the stakes, but Microsoft looks just as determined to stand its ground and close the deal.