Continuing its battle in business cloud arena, Microsoft is taking hard swipes at Salesforce.com by offering huge rebates to customers who switch from Salesforce.com to Microsoft Dynamics CRM Online. Microsoft has sent an open letter to the customers of Salesforce.com and offered a $200 per-user rebate for every customer that switches to them. It clearly reflects that the software giant is increasing its aggressiveness in the cloud arena.

“In making the switch from other solutions, such as Salesforce.com,” Michael Park, a corporate vice president with Microsoft Business Solutions, wrote in that Dec. 6 missive, “you will join thousands of companies that have found that Microsoft Dynamics CRM Online is easier to use, adds value to the technology investments they’ve already made and delivers greater business insight.”

On the other hand, Salesforce.com CEO Marc Benioff reported that their offerings are much better than Microsoft’s options.  He also questioned its rival’s ability by giving this statement at the Gartner Symposium 2010 asking, “How many SAP customers are on the current version?  How many Oracle customers … how many Microsoft? Fractions. This model has to change.”

Besides this aggressiveness, Microsoft also filed a lawsuit against Salesforce.com in May complaining about the infringement of nine patents and consequently, Salesforce also accused it of violating three patents. That’s a different thing that both companies settled their differences in August.

It doesn’t mean at all that this will allow Salesforce.com to lag behind as we are hearing several other developments by the company. A recent update by Seeismic that includes a beta version of Salesforce’s real-time business collaboration.  The Salesforce Chatter will allow one to collaborate within the company and take status of leads and contacts, etc.