This is what I find worrying about the sale to Rakuten:
Buy.com in the U.S.
Buy.com in Canada
There's a reason I'd never heard of Buy.com - they have next to nothing on the Canadian site. That leads me to believe they value the U.S. market more than they do the Canadian one. Will we see another Amazon.com vs. Amazon.ca with Kobo, where the U.S. market gets all this new, neat stuff (apps, cloud service, music, video streaming) and we're left with just ebooks?
For now I take heart in the fact that Kobo will be keeping it's head office in Toronto, but I admit I'm wondering if that situation won't last much longer.