The fully-managed on-demand service, says Rackspace, offers the functions of Microsoft Exchange Server 2003, providing messaging and collaboration solutions and combining advanced mail with shared calendars, contact lists, public folders and task management features. Customers pay for only the mailboxes they use.

Emil Sayegh, director of product marketing, says Rackspace launched the new service because email is becoming an increasing burden on IT departments. Mail, he says, isn't necessarily strategic for a lot of companies. They use it because they have to.

"Managed Exchange is the most popular enterprise email application," says Sayegh. "The problem is that only two or three percent [of that] is hosted outside the company, meaning that a lot of these companies actually have Exchange servers internally.

"We run our lives by email. Email has become mission critical," he says. "Therefore, we're seeing a steady and rapid movement of companies looking for more reliable solutions to their email infrastructure. When a company like Rackspace comes along saying it can offer this managed solution, clients are saying 'wow, that means I don't have to do these things myself and I can dedicate IT resources to other things that are strategic to my company.'"

Sayegh says the Exchange offering compliments Rackspace's existing email solutions, which include its dedicated solution IMail and its managed solution Noteworthy. He says Exchange will be available as both a dedicated and a managed email solution.

"Whether our customers host their Exchange servers with us or are Noteworthy customers, they want the feature of Exchange, the collaboration feature of Exchange, so this is a solution that is targeted to our existing customers as well as new customers that are looking for a reliable way to host their email. Rackspace is the perfect fit for hosting mission critical applications, specifically email," says Sayegh

Although Rackspace isn't necessarily offering Microsoft Exchange in a unique way, Sayegh says the company's advantage is its commitment to making sure that email is up 24-hours a day and is committed to how that relates to the industry. The difference, he says, is Rackspace's hosted exchange offering is better.

"We are not the only company out there offering hosted managed Exchange by any means. But we waited to do this until we could apply our fanatical support to it," says Sayegh. "There are other companies out there that do this, but if you have a problem with your email account, they may not respond to you for 72 hours. We respond to you immediately. We respond immediately and then we guarantee 99.9 percent service level agreements. So frankly, within 40 minutes you're back up and running. In case of a major disaster, other companies commit to getting you back up in 72 hours. In case of a major disaster, Rackspace guarantees six hours. We're just doing it better than everybody else."

The offering, says Sayegh, is likely to expand as Microsoft develops the Exchange solution, a process to which Rackspace is likely to contribute, as a well-regarded Microsoft partner.

"Where we see ourselves expanding into is more collaboration features, as well as working really closely with Microsoft on future releases of Exchange," says Sayegh. "So we're partnering up with them on that. There's going to be lots of things coming down the pipe in the future."