J.ot Down is a simple, sharable online notepad
Going to the site opens up a new note. From there, you just type. There's no formatting with fonts, colors or styles, and no HTML support - just typing. When you pause, J.ot Down will autosave your document and give you a permalink you can use to share it or come back to it. You can also manually save.
That's the entire feature list, as far as I can tell. It's amazingly lightweight, and makes a good substitute for stickies or notepad docs when you're not on your home machine.