One reason I like Smashwords is it gives you the option of also selling your ebooks in other retailers, specifically the Apple iBooks and Sony Reader stores. Sony has provide a slow but steady sales stream, but Apple is interesting because their stores have resulted in some international sales for me.
When you own international rights to your book and publish it via KDP, your ebook is also for sale in the Kindle stores in the UK, Germany, France, Italy, and Spain. But of course, except for the UK, an English language book is not going to do as well in those countries. The Apple iBooks store, however, sells in the UK, Canada, and Australia as well as parts of Europe. For some reason, Tribes has done better in Australia than anywhere else! Maybe it's the desert setting for the opening scene? Or maybe it's the remoteness of the colony world? Who knows!
But I'm happy they like Tribes Down Under!