Ask HN: The Web app that you just write into and register if you want to save?

There was a Web app that someone on here recently showed off. Basically it was just a minimalist page with a big text box and you could just start writing in it and if you wanted to save it you could register an account. It had the theme of being a peaceful/minimalist writing environment. Does anyone remember what I'm talking about? I've literally scoured my browser history and I've searched Google (constrained to this site, ranged over the past month, with several keyword combinations) and I've had zero luck finding it. This is my last resort.