I know the site already supports mobi & epub formats. The site even has a really cool "email to Kindle" feature that I missed. (Too bad my Kindle is MIA right now!)
The FAQ does not address how to get content onto IOS and/or Android devices. I ass-u-me we need to use a computer with iTunes or an Android equivalent, but I really don't know and need an education. :-)
An IOS FAQ is particularly challenging because Apple provides such a seamless ecosystem that users have no need to "look under the hood" to understand how their devices work because they just work. I can already see my sister's eyes glazing at instruction to [d/l & save --> import to iTunes --> IOS device], and many IOS users have a similar usage profile.
Given how ubiquitous Ios & Android devices are, it may make sense to invest some development time into implementing utilities that download directly to the portable devices (rather than computer --> device). Of course, you may already do that, and I just demonstrated the need for an FAQ that covers existing capabilities.