At FutureBook, “namenick” has a post explaining why he sees Kobo as being much better-suited than Amazon or Apple for international expansion. In short, Kobo has much better international content availability.
Where Amazon has been opening separate stores for various different countries and languages (most recently a French store), Kobo makes all content for all languages available from the same store.
One example which shows why Kobo is ahead of iBookstore or Kindle Store – Smashwords. Books from Smashwords are theoretically available at Kindle Store, Kobo and iBookstore. The deal with Amazon doesn’t seem to work yet. There are over 40,000 Smashwords books in iBookstore US, but I can’t find a lot of them in iBookstore PL. So far, if I wanted to buy Polish books published at Smashwords, I could jump either to Smashwords or to Kobo.
He also points out that Kobo’s use of plain-vanilla Adobe DRM on EPUBs means that it is not restricted solely to Kobo’s own e-book store—it can read any e-books that are sold in Adobe-DRM’d EPUB (as well, of course, as the ones sold DRM-free).
namenick makes some interesting points. It could very well be that even as Kobo remains in third or fourth place in the US e-book market, it will still stay in the running by catering to the places the bigger US names aren’t touching.