Kindle and other ebooks

These days, I try to buy books to read on a Kindle.  There are other formats and other readers.  The two main sources of ebooks other than Amazon that I am aware of are Barnes & Noble and Google Books.  So far, I have not found a book I want on B&N or GB that wasn't already available for the Kindle.  In electronic format, I get the book very quickly, within a couple of minutes.  I don't need the postman or the UPS driver.  I don't need to shelve the book or dust it or heft it.  Recently, Wired or somebody stated that an ebook inside a Kindle has a form that means that some tiny atomic or sub-atomic particles must change and that the new form is a tiny, tiny bit heavier than the unchanged form.  Therefore, a Kindle weighs sub-microscopically more filled with ebooks than it does empty.  The estimate was that 1500 ebooks make the Kindle weigh more by 1/100 the weight of a single bacterium.  Not enough to notice.  

Many public libraries loan books electronically.  In addition, Amazon allows Kindle owners to borrow a book a month and keep it as long as desired.  I borrowed a book, didn't like it but I found I still have to wait a month to borrow another one.  If desired, Amazon will rent an expensive text to a Kindle owner for less than the purchase price but it can only be kept a week or two.

Amazon makes software available free on its web site that allows books to be read on a computer, regardless of whether the owner has a Kindle or not.  I assume Nook does the same thing.

The Kindle makes highlighting a passage from a book very quick and easy.  All highlights in a given book can be displayed in a single file very easy.  They come up in order of the book's pages and it is quick to move from one highlight to another.  The highlights made on a Kindle can be unloaded from the Kindle onto a computer in a file that can be read by Word or other word processing software.  The highlights are also stored on computers at kindle.amazon.com. and can be viewed there.

Some ebooks can be reformatted for Kindle by the free program "calibre", but the program states that only books without DRM (digital rights management) can be reformatted.