Observations concerning the Google ebook platform

I thought it would be useful to summarize some of the properties of the Google ebook platform, some of which are unique.

• Not unlike Amazon, B&N, etc., all of the ebooks associated with your Google account (free or purchased) are stored in the cloud with your Google account.
• The iOS & Android apps do not download PDF/ePub as such, but rather use some Google-proprietary storage format. The Google ereaders do not allow 'side-loading' or 'open with' functionality, and can only open content that comes from Google's cloud storage.
• The iOS & Android apps, web ereader do not use Adobe Reader Mobile technology, unlike other Adobe DRM-based reading systems. Google does not license the Reader Mobile software. As such, neither the Google mobile apps or the web ereader need to be authorized with an Adobe ID. 
• Adobe DRM is applied only for DRM restricted titles, when downloading for use in a non-Google ereader (which needs to be authorized with an Adobe ID). Google licenses the Adobe Content Server for this purpose.
• The Google instructions indicate that you need Adobe Digital Editions to download an ePub or PDF file. That's not strictly true: you can use any application that is authorized with your Adobe ID to open the .acsm file you get from Google, and download the ePub/PDF. For example, Bluefire can do this on iOS. 
• So the Google ebook platform operates independently of Adobe technology, though it works with platforms that use it.
• Some purchased titles do not allow downloading and must be read with the Google web ereader or one of the Google mobile apps.
• Google now requires a credit card on file, even if you only want to get free books.
• Apparently the Google apps and web interface consume a variety of CSS-free ePub whose capabilities are not well understood. Yet another challenge for ebook designers who want their ePubs to look good everywhere...