Originally Posted by Agama
So if I wanted to make MOBI's from ePub using calibre and simply send them directly to a Kindle then it would be ok? The restriction is only for books uploaded to Amazon? (What does uploading them to Amazon achieve? Since I don't have a Kindle - yet! - this is foreign territory to me.)
KindleGen is only used if you want to upload a book via the Kindle Digital Publishing programme to SELL on Amazon's book store. Yes, Calibre's Mobi files work absolutely fine for sending to a Kindle.