Japan's Rakuten, Inc. has reported that Kobo, Inc., its recent acquisition, saw a ten-fold increase in its number of ebook customers over the holidays. Kobo has not released official sales numbers yet, but the company says it has had "hundreds of thousands" of new device activations each day since Dec. 24. Kobo also offers its own content store.
Similarly, Amazon claims over 4 million Kindles were sold through December, and Barnes & Noble says that unit sales for the Nook device alone were 70% higher than the 2010 holiday season. B&N claims that it sold "virtually its entire inventory of NookColor and E Ink devices" during this past holiday season.