Mario Kart TV, a website where you can upload and watch races from Mario Kart 8, is due to be closed by Nintendo on Apr. 8.
The news was first announced with a notification which states:
“The Mario Kart TV website, which lets you watch highlight videos posted from Mario Kart 8, will be closing down as of 07:00 (UK time) / 16:00 (AEST) on Tuesday 5th April 2016. We are very thankful to the many people who have used this website since it launched in 2014.
Even after the website shuts down, it will still be possible to watch Mario Kart TV and upload highlights from within Mario Kart 8 itself. Highlight videos uploaded to YouTube from the game will not be deleted after the website shuts down.”