Comixology has announced that they are now supporting your Kindle comics and graphic novels. You can now sign into their updated Android, iOS or Fire OS app with your Amazon user credentials and it will automatically sync all of your purchases. Alternatively if you are an existing Comixology user you can merge your Amazon account.
Comixology is the largest digital comic re-seller in the world. They account for the vast majority of sales for DC, Marvel, Archie, GI JOE and many other top publishers. Not only do they sell the comics in their own app, but they have developed custom apps for these publishers as well.
Amazon acquired Comixology in 2014 and many people who bought comic books were fairly disgruntled with the move. This was primarily attributed to the elimination of in-app purchases via the flagship app for iOS. This was done because Amazon is fairly notorious for not wanting to pay Apple a % of each digital transaction.
I think its fairly exciting that all of your Kindle comics and graphic novels can be imported into Comixology. Many users are likely going to gravitate towards the app because it provides a far superior experience to Amazons own comic book reading software.