After it launched an invite-only pilot program last year, Microsoft released a public preview version of Outlook.com Premium in October. Yesterday, the company officially launched the subscription service, but only to those in the United States.

Microsoft hasn't made any announcements about bringing Outlook Premium out of its preview state; it was Thurrott.com that reported the news. Anyone based in the US can subscribe to the service, which adds a number of features to the regular Outlook.com program.

Outlook Premium features no banner ads, much like the ad-free version of the regular Outlook that Microsoft offers for $19.95 per year. That means you can view all your emails, photos, and documents without the irritation of constant graphical advertisements.

You can also create five personalized email addresses with your own custom domain names, which is good news for those users who prefer something other than a @outlook.com, @live.com, or @hotmail.com address. The domain name from Microsoft will be free for the first year, and anyone who already owns a domain can use it with the premium service free of charge.

Outlook Premium lets you easily share calendars, contacts, and documents (via OneDrive), with sharing relationships set up automatically between the people who have email addresses on your domain.

You can subscribe to Outlook.com Premium for $19.95 for the first year as long as you do so before March 31, 2017. The price will then increase to $50 per year. If you're using a Microsoft custom domain, it will cost $10 per year after the first free 12 months.