Microsoft has reworked its browser-based Hotmail into a free, socialized, Facebook-friendly service it's calling Outlook.com, borrowing the name from its Office e-mail client.

The idea is to stop Google's Gmail from eating into its turf.

With 324 million users Hotmail is the largest online e-mail service on the planet. It has an estimated 36% of the global market to Gmail's quickly advancing 32%. Yahoo Mail also has 32%.

After eight years of neglect, Hotmail has been given a simple Metro-like UI and an uncluttered Googlesque look that's tailored to small devices as well as PCs and Macs.

It'll separate out e-mail with photo or document attachments. Messages with Office attachments will integrate with Office Web Apps for previews of Word, PowerPoint and Excel documents. Picture attachments will come up as a slideshow.

It's supposed to recognize YouTube videos, calendar appointments and tracking updates from UPS and FedEx.

The remake also includes spam-filtering for dealing with the torrent of junk mail the Internet delivers. Mass messages are dumped into separate folders.

Users can connect directly with their Facebook, LinkedIn, Twitter and Google+ accounts; sync address books; and start a Facebook chat from inside Outlook.com.

Outlook.com integrates with Microsoft SkyDrive cloud storage. Skype will eventually be built in.

Unobtrusive text-based ads appear on the side of the inbox screen; they're not in the messages. Microsoft's promising not to use the mail for personalized ads.

Hotmail will apparently remain around until users sicken of it and migrate.

There's a preview at www.outlook.com.

In six hours or so, Microsoft tweeted that Outlook.com got more than a million people signing up.