The situation doesn't sit well with at least some BPOS customers who were eager to migrate to Office 365 right away and expressed their disappointment that they won't be able to in .

"Wow, so I guess the solution is to terminate service and sign back up, or maybe just terminate service and go elsewhere. Between the recent significant decrease in the support team's ability to, well, offer support and this, it's making it hard to stay happy with the service," a BPOS customer wrote in the discussion thread. "Can't argue with the business logic though -- they already get our money. It's way more important to push the service to new folks so they can collect their money as well. If only the marketing folks took the time to think about what happens when they alienate the customer base."

Office 365, a cloud-based collaboration and communication suite, includes online versions of the 2010 editions of Exchange, SharePoint, Lync and Office, offered through a variety of configuration options, all billed on a per-user-per-month basis. Industry observers view it as a much stronger competitor to Google Apps and other rivals than BPOS, which lacks the Office components and whose applications are based on the 2007 versions of their on-premise counterparts.

A Microsoft spokeswoman said that the intention to proceed with care when dealing with BPOS-to-Office 365 migrations isn't new and neither is the plan to have a pilot program following the product's general availability.

However, judging by their surprised reactions in discussion forums, the plan is news to some customers. Those tuning in via webcast to the launch event wouldn't have found out either. Ballmer didn't specifically address the issue and the overriding message at the event was for customers to embrace the product right away.