Microsoft yesterday officially launched the online versions of its Exchange and SharePoint software platforms, but only to businesses in the United States for now.

"We can help you save money," Microsoft Business Division President Stephen Elop told the crowd at the US launch of the offerings, saying Microsoft estimated that companies could save at least 10 per cent by letting Microsoft run their messaging and collaboration software for them in the company's own datacentres.

One of the early customers of the software-as-a-services (SaaS) offerings is video retailer BlockBuster, which has been using Exchange Online for about six months. Blockbuster chief information officer Keith Morrow said in an interview that Microsoft's online services had arrived at a good time for the company, which had been using a several-generations-old version of Lotus Notes.

Morrow said the video rental company needed to make a change of some kind, and the option to move to Exchange without having to bring that skill set in-house was a key selling point, as was the ability to offer better mobile options, including Outlook Web Access and iPhone support.

"We just couldn't justify the up-front investment," Mozack said.

Microsoft's Ron Markezich said about two-thirds of early customers were moving from Notes to Exchange. But even as Microsoft continues to target those moving from Lotus Notes, the company faces the threat of its own Exchange customers moving to other hosted options, including Google Apps. Just last week, Serena Software said it was switching to Google from Exchange in a move it said would save it US$750,000 a year, according to several reports.

At the event, Elop made Microsoft's familiar case that, while the cloud is great, customers are better served by an option that allows software to run on customers' own machines as well as over the internet.

Elop said Microsoft was adding thousands of servers to its data centers every month. Although Microsoft Online is initially aimed at Exchange and SharePoint, the goal is to offer a hosted option for all of Microsoft's server software.

"We expect all of it be available in this way in the near future," Elop said.

The software maker said last year that it would offer the hosted option for large businesses, later expanding the offer to businesses of all sizes. At last month's Professional Developer Conference in Los Angeles, Microsoft also confirmed that it would offer web-based versions of its Office applications, including Word, Excel, and PowerPoint.

While many of those at Monday's event were the company's early customers and partners, not everyone at the event was ready to sign off. I spoke with a municipality that was highly interested in Microsoft's product, particularly as it plans to move from GroupWise to Exchange.

Still, with a dearth of other governments to point to, this CIO told me that he still faced challenges in getting the city's upper management and government to sign off on the deal.