When most people play the word association game with “e-Reader,” the most likely answers will be Amazon, Kindle or iPad. However, it seems that Toronto-based Kobo is quickly joining these familiar names.

The company sold four million of its e-readers in 2012, bringing its customer base to more than 12 million registered users. And, it has doubled its growth year-over-year

“In December we celebrated Kobo's third anniversary as well as the biggest month for the company yet," Kobo CEO Michael Serbinis said in a statement. "Millions of new users registered with Kobo in December alone, annual device sales soared with millions of Kobo eReaders bought, and eBook sales nearly doubled from the previous year. 2012 was truly outstanding for our company and our network of booksellers and retailers around the world."

Kobo’s product line is similar to its rival Amazon’s Kindle line, with three E-ink-based readers, the Kobo Touch, the Kobo Mini and the Kobo Glo. The company also recently launched the Kobo Arc, a seven-inch tablet that like Amazon’s Kindle Fire is based on Android (News - Alert).

Kobo has popular titles like “The Hunger Games” and “Fifty Shades of Grey” available in its online store.

What sets Kobo apart from Amazon is its commitment to an open reading experience, instead of locking users into a proprietary format. It also makes reading applications available on iOS, Android, BlackBerry (News - Alert) and Windows.

The company hopes to ride the growing wave of e-reading.

“We are seeing tremendous international opportunity to bring eReading to new markets, and help transform the industry through technology innovation," added Wayne White , EVP and GM of Devices, Kobo. "The transition from print to digital, the evolution of devices, the application of technologies, and the market adoption of eReading around world is in its infancy. Kobo's trajectory of growth reinforces that people want to read more – and on a variety of devices." 

The company seems to be most popular in its native Canada. Canadian readers read the most pages on Christmas Day, with an average of 200 pages each. Americans followed at 160 pages each and British readers with 93 pages. Kobo claims that users have read 22 million pages total.

The most popular languages are English and French, which appear to reflect its Canadian popularity, with Japanese the third most popular language.

Kobo is also providing new opportunities for authors to self-publish books with Kobo Writing Life. One notable success is Sylvia Day’s “Wish List,” which rose to the top of Kobo’s chart extremely rapidly.

“Kobo's self-publishing program has engaged a wide variety of publishers and authors to quickly publish new and back-listed titles with Kobo," Mark Lefebvre , director of Self-Publishing and Author Relations concluded. "We've designed Kobo Writing Life to put the power of publishing into an author's hand without impeding them with hidden fees. It's the most flexible platform available today and as a result, 98 percent of our authors publish works internationally."

The company plans to expand internationally into Russia, India and China in the not so distant future.