[stonetools]

You know, it's been interesting reading the techies bang on about embedded fonts , format choices, typesetting philosophy, etc. , but let's be blunt: the decision as to whether Pottermore will offer ebooks in mobi format will be ultimately a business decision.
What will matter is that Amazon and it's customers represent 60 % of the ebook market. Those customers for the most part read their ebooks in mobi format on Kindles. There is no way on God's green earth that Pottermore is not going to craft a custom solution for those customers. That solution isn't going to be Calibre, or format conversion, or demand anything technical whatsoever of those customers. Rather, it is going to be a process as simple as those customers buying an ebook on their Kindles.
The easiest way to do that will be to simply to have the books available in mobi format at the Pottermore site. There will be a big old button saying " To buy books for your Kindle, click here" and that will be start of the buying process that ill end with them downloading the ebook in mobi format. Those customers will be unaware of the benefits of ePub. And will most likely not care in any case . All that will matter is that they will finally be reading their beloved books on their chosen reading device.