The Great Hotmail-to-Outlook.com Transition Begins When Microsoft introduced a preview version of a fresh and inventive webmail service it called Outlook.com last August, it was pretty clear that it was telling the world that it intended to start winding down its venerable Hotmail sooner or later. Now it's official. The company is announcing that Outlook.com is coming out of preview mode and is now officially available worldwide. And so it's going to start moving more than 300 million Hotmail users over. They'll be able to keep their Hotmail.com e-mail addresses - or Live.com or MSN.com, if that's what they've got - but the Hotmail service and brand will be going away. The transition will be gradual: At first, the Hotmail faithful will get e-mails and other alerts telling them about the switchover. They'll be able to make the jump immediately, or postpone it. But by the end of the summer, the company intends to have moved all Hotmail users over to Outlook.com. For most of those people, that should be a good thing - or at least, as forced transitions go, not a bad thing. While it's impossible to underestimate the ferocity with which some folks prefer to clutch onto whatever they've already got, Outlook.com is a far better service than Hotmail, with a radically decluttered interface and useful new organization tools. I also like its interface - which is a variant of the Windows 8 look formerly known as Metro - better than Gmail's. Yet it's also recognizable as having a family connection to Hotmail, reducing the chances that anyone will be bewildered by it or will lose a favorite feature once the switchover is complete. At the moment, Microsoft says, Outlook.com has 60 million active members, a third of which are Gmail users. Presumably some of those are true defectors from Gmail, while others use both Gmail and Outlook.com. Once the Hotmail transition is complete, Outlook.com will have hundreds of millions of users, giving it the same sort of massive scale as Gmail (425 million users as of June 2012) and Yahoo Mail (281 million users as of December 2012). And Microsoft seems to be serious about winning over lots more users from Gmail and other services: It's planning to advertise Outlook.com heavily in all sorts of media. Here are a couple of splashy TV spots - both of which, unlike the current Scroogled campaign, are devoted to making people feel good about Outlook.com rather than bad about Gmail. While I'm favorably impressed by Outlook.com, I'm not considering dumping Gmail myself anytime soon; Google's service remains a much richer platform, with additional useful features, mobile apps and support from third-party apps and services. Microsoft says to expect more Outlook.com features now that the service is out of preview mode, including Skype video calls and a calendar, both of which the company first promised when it announced the service last year. I'll be keeping an eye on it - an Outlook.com which retained its sleek look and competed with Gmail in depth and breadth of capabilities could be spectacular. Even Gmail users who have no intention of leaving the service should be happy that Outlook.com exists. Just as Microsoft's Bing gives Google's search engine its only serious competition, Outlook.com is poised to be Gmail's most imposing rival. I'm still getting used to the notion of Microsoft, of all companies, being a plucky underdog - but I'm glad it's giving Google at least two incentives to avoid resting on its laurels.