I use the Amazon Cloud Reader and PC Reader, but I can only view books purchased through Amazon in them. In fact, it won't let me deliver other books - those I emailed to Amazon for conversion or created in some other way, like using the Chrome extension - to those readers, at all. See the image ...

Is it useful or advisable to get screen protection for eReader? Also does anti-reflective layer makes any good or bad difference with the eInk screen?

I have heard that I can use calibre to create a cloud with all my books, not just ones from a specific vendor. How would I do it?