On Wired’s Epicenter blog, Tim Carmody writes about why he thinks that the main global e-book competitor Amazon has to worry about is Kobo. He points out that while Amazon and Apple have been making highly visible splashes with their new hardware or e-publishing initiatives, Kobo has quietly been building support from a multinational network of bookseller partners, including major booksellers in England, Hong Kong, and France. And now its acquisition by Rakuten adds all of Rakuten’s previously-existing worldwide digital book and media operations to the Kobo brand.

“An e-book reader will ultimately not be only about selling books,” Rakuten’s Pierre Kosciusko-Morizet told the BBC in November. “It’s about potentially selling other digital goods, and it’s also about being in consumers’ homes with a hardware device.” A device like Kobo’s new Kindle Fire-like Android tablet, the Vox.

And Kobo Executive Vice President Todd Humphrey told Carmody that “to be perfectly candid, the only company we see as a competitor [in Japan] is Amazon.”

Carmody also points out that Kobo has also been quicker than Amazon about getting its devices out into international markets—and that Barnes & Noble hasn’t even started building an international market yet.

It’s funny how quickly Kobo looks to be changing from “that also-ran who isn’t Amazon or B&N” to a major internationally competitive power. Though perhaps it’s really not really all that much of a change—it’s just that people are starting to pay attention more.

Correction: Changed Kobo VP’s name from Bradley to Humphrey, above.