Just six months after launching a preview version, Microsoft’s new email service, Outlook.com, has hit 60 million registered users, the company announced today.

Outlook — not to be confused with the enterprise-level email service of the same name — is basically an overhaul of Microsoft’s Hotmail email service, which itself has over 325 million users. The new service first launched this past summer and offers a fresher, consumer-focused take on email for people who normally wouldn’t ever give Hotmail a second chance. Outlook’s ultimate purpose is to tie together all of Microsoft’s services into one nifty package that integrates news, email, video chatting, instant messaging, and more.

Today Microsoft is also rolling Outlook out of preview and allowing the public to sign up. Additionally, the company said it will begin transitioning Hotmail users to the new Outlook service. I’m guessing the 60 million total Outlook users is comprised of new users as well as those that have already transitioned over from Hotmail. Now that Microsoft will be pushing its remaining Hotmail users over to Outlook, it shouldn’t take long for the service to hit 100 million users.

Microsoft started marketing for its Outlook service earlier this month with a new advertising campaign slamming top email competitor Gmail. The ads imply that Google is screwing its users over by using their private data to show advertising — a practice Microsoft has dubbed being “Scroogled.” However, its latest ad (embedded below) definitely puts a focus on what’s good about Outlook rather than what’s wrong with its rivals.

It’ll be interesting to see if Microsoft can seriously put a dent in Google’s credibility with the new ad campaign and slicker email service competitor.