The debut of Salesforce for Google Apps on Monday wasn't particularly surprising, given that the two companies announced a partnership last June. But the tightening embrace between the two shows that Google isn't going to leave Microsoft's competitive moves unanswered.Microsoft, as many are aware, has been trying to figure out how to swallow Yahoo in order to strengthen its search advertising business, an area Google dominates.

And now Google is returning the favor by holding hands with Saleforce.com as a way to bolster its enterprise business, an area Microsoft dominates.

If something can be done about all the egos involved, Google wants to buy Salesforce.com. But even as mere partners, Salesfoogle will put pressure on Microhoo.

"With Google on its team, Salesforce.com poses a greater threat to Microsoft, which is a competitor to both companies," IDC observed in a research note issued on Monday.

IDC predicts that the combined Google and Salesforce.com will prove appealing to small- and medium-sized businesses and will help Google generate both service-based and ad-based revenue from companies around the world.

Taking down Microsoft won't be easy, however. According to IDC, "our research shows there has been no attrition or substitution of Microsoft Office productivity tools by Google Apps."

But that may only be fair, given that Windows Live Search hasn't exactly been stealing market share from Google, either.

According to figures released by ComScore on Tuesday, Google's U.S. search share reached 59.8% in March, up from 59.2% in February. Yahoo's U.S. search share dropped to 21.3% in March, from 21.6% the previous month and Microsoft's U.S. search share declined to 9.4% in March, from 9.6% the month before.