First of all you should register and get a @iduokan address to use this service. (on Duokan's settings page)
at the buttom right of the page there is an option to use the site in English.
(ie this link http://dog.whycai.com/?lang=en_US
then login with your google account. > use "Manage your kindle" to set your duokan/kindle mail address> turn back to feed subscription page (http://dog.whycai.com/
) >Subscribe to a feed.
You can also add a feed to subscribe.
Please let us know the result