"I'm not so sure that [social networking] will be the thing that drives people to it, or to use it," said Miller of Outlook.com. "Instead, it will more about how [the service] helps you get things done."

Miller pointed to the integration with SkyDrive and the Office Web Apps -- the in-the-cloud versions of Excel, PowerPoint, OneNote and Word -- as key to Microsoft's strategy.

Outlook.com provides each user with a free SkyDrive allotment of 7GB, and will open Excel, PowerPoint and Word documents with the online apps. SkyDrive is particularly critical to Outlook.com, as file attachments, including those sent by others, are deposited in the cloud, allowing users to send and receive very large files that might choke an email server or be rejected because of size limitations.

Outlook.com's ties with Office Web Apps lets users open Excel, PowerPoint and Word documents even if they don't have a copy of Office handy. (Image: Microsoft.)

Microsoft's used the Hotmail brand since 1997, when it acquired the service for an estimated $400 million. But the brand is old, said Miller, while others have said the service lacks the panache of Gmail among the technology elite.