It’s Tumblr’s April Fools thing. Something on the side bar came up and, if you clicked it, changes your username to something along the lines of “ArborixCorp” or other variations. If you click on it again it brings up these little app things, including that notepad, some stock thing, and a calculator that gives you the wrong answers. Also the little paperclip ripoff that I got rid of with adblock because it was becoming way too annoying.

That’s about it in a nutshell :U