“The rate of downloading is growing exponentially,” said David Steinberger, CEO and cofounder of Comixology, the digital comics distributor and marketplace, describing the sales of digital comics in an interview with PW at their booth on the floor of the San Diego Comic-Con International. Launched at Comic-Con in 2007 with about eight publishers and less than a hundred comics, Comixology now offers more than 40,000 titles via a digital reader and Web site and consumers can read and buy comics across every platform and device from phones to tablets.

“We’re an iTunes and Kindle for comics,” Steinberger said, and the company’s growth has been something to behold. Comixology registered its 100 millionth download in late 2012. “It took us three years to get to 100 million downloads and nine months later we’re at 180 million downloads,” he said. Based in L.A., New York and now with a Paris office, Comixology has about 100 employees and not only sells comics through its own app, Comics on Comixology, but also offers a white label service that develops and powers the apps of publishers like Marvel and DC and many others. Very quickly, Comixology has become the dominant digital distributor and retail marketplace for digital comics.

Steinberger credits a couple of events with spurring the growth: the launch of the iPad in 2009 as well as DC Comics decision to go with “day and date” releases for print and digital in late 2011—using the New 52 relaunch of its superhero universe as kickoff, DC began releasing print and digital titles of it comics on Wednesday of each week. The decision pushed the sales and appeal of digital comics to a new level and while physical retailers were initially fearful of the impact of digital, retailers now hail the move for bringing new comics readers into their stores as well as creating a new level of interest in comics for consumers. “DC going day and date was an enormous event for us; all the publishers followed their lead,” he said.

Earlier this year, the company launched Comixology Submit, a kind of hybrid self-publishing platform—anyone can submit a comics title, Comixology will review it and if it offers an adequate level of quality, they will process it with their technology and offer it for sale with a 50% split of revenue. That means any creator—from Eisner award winning cartoonist Becky Cloonan to an aspiring creator working on their first comic—has a shot at global distribution (40% of its signups are from outside the U.S.) on one of the most popular digital comics platforms around the world.

Since its launch in the spring, Comixology Submit is now offering about 150 series, though Steinberger acknowledged the service has become a victim of its own success. “We have more submissions than we can review,” he said, “it’s a good problem to have but its still a problem.” And the problem stems not from the number of submission but the technology: “the files they submit must be high quality. We give creators clear instructions but people aren’t giving us the right quality and combined with the volume, it means creators will see a slowdown when it comes to getting Comixology Submit projects approved and released.”

On other fronts, the company continues to grow internationally—despite offering only English-language, the Comixology app is the top seller in a numer of foreign markets. But this year the company added a French office and French-language comics. Comixology now offers about 500 French titles for sale, representing about 40% of the French comics publishing market and is adding more. The French Comixology app is the top selling book app in France (its always among the top selling books apps in the U.S.). And most recently the company began offering subscriptions—users can signup to automatically pay for and receive new issues and volumes—and bundles, or groups of digital comics grouped together and priced at a discount. Publishers put related or perhaps creatively unrelated titles together and offer a big discount off the list prices, sometimes as much as 50% off.

“Bundles are a great entry point and really great deal. If you love, say, Brian K. Vaughan’s Saga and The Walking Dead, we’ll put them together with a couple other books people really want and discount them,” he said. “Over the next six months you’ll see a lot of experimentation by us and our publishing partners in creating bundles.”