I am pretty sure this is what it means. It is a day that people post photos of cats on the internet and make memes? Sounds good to me, I like it when people love cats so much that they take photos of them and then let everyone else see them, pretty cool ain't it?
Like here, see I was just sitting on a chair, being a good cat, just resting and one of them humans just started taking pictures of my face, it is okay, it is Caturday after all so I didn't smack them this time.
