http://apprenticealf.wordpress.com
Many books have DRM which prevent you from reading them on the devices
you choose (and only on officially vendor-approved devices). With this, your options become more flexible, and you don't have to worry the store might close down (several stores have, back in the day. Also an ever-present fear with Barnes & Noble Nook, who aren't looking so good.

)
Many people here alf their books.