Hasn't eReader gone out of business? That's the format I had a few books in, and a while back I got an e-mail offering me a chance to convert them to Nook format before they stopped being offered in eReader, and I missed the window because I was too busy with other stuff. So now I'll no longer be able to transfer those books to a new computer when I replace my current one.
Nope, I just got a new Kobo aura(to replace my kobo glo) and Amazon Kindle is still very much in business. I just prefer reading ebooks on an e-ink screen rather than an LCD screen on a tablet.