Develop active content for e ink kindles

Do you know that you can actually develop active content for e ink kindles (we are not talking about kindle fire app development which is another story)? Did you have the free games " Mine Sweeper " , " BlackJack ", " EveryWord", and "Shuffled Row" installed on your e ink kindles? If no, I would suggest you get them. They are FREE and fun. These games are perfect examples of e ink kindle apps.
To develop such apps, we got to have Kindle Development Kit (KDK) first.

1. Request to become a developer.
2. Download the Kindle Development Kit
3. Develop, test and submit content. User revenue will be split 70% to the developer and 30% to Amazon net of delivery costs of $0.15/MB.