1) Looks like the app can’t handle passwords with symbols in them.

2) http://en.wikipedia.org/wiki/OPDS.  I use calibre to manage my books, and I have the calibre OPDS server always available within my internal network in order to get books.  It’s much more convenient than having to copy/sync them to dropbox or skydrive or use a proprietary sync method like iTunes or the bookviser sync.  Maybe the “regular” user wouldn’t notice, but then the “regular” user is just going to use the Kindle app anyway. Non-DRM-supporting readers like this and Freda target more “advanced” readers, since they have to be able to do things like remove DRM from purchased books in order to read those books in the app.

3) Hyphenation, the act of splitting large words at line breaks by adding hyphens (-), to avoid large gaps in text that which can form annoying “rivers” of whitespace through a page of text and to maximize character/word density per line.  It’s a difficult thing to do well programmatically (note that Amazon doesn’t hyphenate on any of their Kindle readers, the devices or the apps for various operating systems), but it can be done.  Freda does it.  iBooks does it.  Stanza does it.  Nook does it, at least on their eink devices.  I get that many people don’t like hyphenation, especially when poor implementations can hyphenate weirdly, but on a phone-sized device I’d rather have weird hyphenation with more characters per line than no hyphenation and fewer characters per line.  I find the former to be more readable.

4) The font/color settings are implemented as a pivot control (multiple pages that flip horizontally with headers).  Within the pivot pages are slider controls to change things like font size and margins.  When you use a slider on a pivot page and you don’t increase the hitbox for the slider thumb (the default style for the metro slider has a tiny thumb that’s almost impossible to hit), you end up switching pivot pages more often than not (and this often happens even when you do increase the thumb hitbox, though I’d say that’s a bug in the slider control itself).  I challenge you to show me anywhere in the native WP7 interface where Microsoft has even used a slider at all, much less where they’ve put a slider on a pivot page.  Note that toggle buttons (the slidey on/off “switches”) often have similar issues when used on a pivot page, where if you try to swipe to toggle the button rather than tap you end up also changing the pivot page.

5) Reading fiction doesn’t remove the need to render inline images.  Chapter header images and chapter footer images, maps, etc are all found in many fiction books, and not rendering those images reduces the experience of the book.  Sure, you could read without those, but then you can also read without discernible chapter breaks, CSS styling, and other “fit and finish” type issues that make the experience polished and enjoyable rather than a straight slog through raw text.  It’s why I keep my books in epub rather than plain text, for example.

It turns out the problem is with symbols in passwords.  They work on the website but when you try to use them in the app you get a completely useless error message.