Still new to this eBook world. In my second day of ownership of the 650.
I discovered that sometimes I might have an option of formats when getting content. So what is the difference to me if the same book can be had in lrf, ePub, PDF, or rtf. I guess they all work in the reader okay. Do the fonts display differently?
Also, I just started to study and download calibre. While reading the description, I discovered that somehow it converts books to whatever format I want. I don't know what format I would want.

Why would someone want to convert a format that is already readable on their reader?