After first launching Club Nintendo in 2008 and distributing registration cards in hundreds of Wii, Wii U, DS and 3DS games; Nintendo have announced that they are discontinuing the program. In its place will be a new membership program, with more details on it to be announced soon.
The discontinuation of the program will follow the following schedule announced by Nintendo:
April 1st 2015: From this date, Nintendo will no longer include product registration cards with its packaged products, so such products cannot be registered in Club Nintendo. You may still find product registration cards in products that were in stock before this date, however.
April 20th 2015: Termination of the registration of digital products downloaded from Nintendo eShop. Digital products obtained from Nintendo eShop after this date will no longer appear in the My Registered Games & Systems page in Club Nintendo. In addition, surveys for download software titles will no longer be available.
September 30th 2015: End of Club Nintendo programme. All Club Nintendo features, such as signing up as a new member, logging in as a registered member, earning Stars, and exchanging Stars for items from the Stars Catalogue will no longer be possible from this date.
Therefore, if you are like me and have a huge stockpile of unclaimed registration codes, you may want to reclaim them sooner rather than later. Any stars not claimed after the end date will be lost.