It allows you to read with your Kindle reader ebooks that were saved under other popular formats (en.informer.com)
This model basically only read books that were purchased from the Sony Japanese book store and had no support for PDF or other popular formats at the time, such as Microsofts, Nokia, or Palm. (goodereader.com)
Make sure you go for one that is editable in doc format or other popular formats so that you can print a copy easily or ensure that when you mail it to recruiters, it will not go into the trash. (template.net)