The multiplatform note-taking program Evernote has announced it now has more than 10 million registered users. At the start of this year, the company reported it had 6 million users, so it's seen particularly tremendous growth so far in 2011.

The company also noted that the number of its premium users, who pay $5 a month for bigger uploads and better collaborative tools, has more than doubled in the same period. In January 2011, Evernote had some 200,000 premium users, and now it has over 400,000.

Evernote launched into open beta on June 24, 2008 with the goal of helping customers keep notes in sync across different computers and mobile devices. In that time, the service has pushed itself on to many platforms, with apps for Android, BlackBerry, iOS, Palm, Windows Mobile, Mac OS, and Windows.

Evernote also shared some interesting statistics for the number of platforms that its users log into. 25 percent use just one platform, 46 percent use two, 18 percent use three, 7 percent use four, and 4 percent use five or more. In short, most users use more than one, and so the decision for Evernote to go multiplatform is seriously paying off for the company.

Evernote allows users to easily capture and organize information of various types, including text notes, printed and handwritten text within images (or even from a blurry cell phone snapshot), clippings from other applications, and more into what they call a "continuous roll of paper." All data is run through a series of recognizers that makes any text within the various note formats accessible and searchable at any time.

"Ten million users seemed like an inconceivable number when we were getting ready to launch the service into open beta less than three years ago," founder and CEO Phil Libin said in a statement. "Well, it wasn't literally inconceivable; we actually put it on business plans and investor pitch decks and everything. Yup. 10,000,000 users in three years. That's what we told people. We had really pretty graphs showing the projections. Reality is much more impressive than projections."