The countries are: Austria, Belgium, Canada, Denmark, Finland, France, Germany, Ireland, Italy, Japan, Netherlands, New Zealand, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

In November, Microsoft opened the offering to businesses in the U.S. The applications are run on servers in Microsoft-operated data centers, delivered to corporate end-users via Internet and sold on a subscription basis.

Microsoft first articulated its online strategy for the vast, highly profitable Business Division in October 2007. More recently, it announced plans to move pieces of its Office suite online.

Eron Kelly, senior director in Microsoft's Business Online Services Group, said the company expects 50 percent of its Exchange and SharePoint usage to be delivered online.

"We do see this as a major trend for Microsoft and the industry," he said.

Also in April, Microsoft will introduce online services for "deskless workers," who don't have regular access to corporate e-mail. The package will include access to Exchange and SharePoint online for $3 per user, per month. The full online services suite includes those programs, as well as Office Communications Server for corporate instant-messaging and presence and Office Live Meeting. It costs $15 per user, per month.

Microsoft also sells subscriptions to each service individually, but it gives companies that buy the whole package a substantial discount.

The company also landed another major customer for Microsoft Online Services: drug giant GlaxoSmithKline. With more than 100,000 employees, Glaxo will be the largest customer so far for this online offering. A Glaxo executive said in a blog post the company expects "to reduce our IT operational costs by roughly 30% of what we're spending now and introduce a variable cost subscription model for these technologies that allows us to more rapidly scale or divest our investment as necessary as we undergo a transformational change in the pharmaceutical industry."

Microsoft has said it expects companies to save between 10 and 50 percent by using Microsoft Online, depending on if they switch from running the same Microsoft software on their own servers (less savings) or if they replace legacy systems (more savings).

Glaxo previously used Lotus Notes from IBM and Postini from Google, Kelly said.