I saw the first image - Cats just want to have fun - on Tumblr, but with no link back to its source so did a little research to find out more about Tati Ferrigno. Pretty sweet illustrations!
Also, I actually started my own Tumblr which is pretty hilarious because I've never been much of a fan. Then I realized how much fun it is - much like Pinterest - and I kind of got hooked. It's become my internet happy place, where I post images of fuzzy kitties, bouncing bunnies, pretty pictures and so on.
Like I needed another internet image-sharing interface (ha!)...