[Updated] Wrttn.me is an awesome Web notepad, supports Markdown
[UPDATE:] As it turns out, wrttn.me is a clone of wrttn.in. I have now amended the links in the screenshot to point to the original tool, after verifying the fact. The review below is still valid for the original tool (all the more so, in fact). Thanks to alert commenter nuttendorfer!
When I first laid eyes upon Wrttn.me, I couldn't help but notice how spartan it all was. There was nary an image in sight and no flashy CSS3 effects, much less any Flash. The whole thing was just ... text.
And then I started digging in, and I discovered a surprisingly powerful, well-thought-out tool for sharing notes (with optional embedded images and videos), collaborating on them, and getting feedback on your work.
Wrttn.me doesn't require you to log in. Much like PiratePad, you just start writing. I should mention, though, that it doesn't have synchronous real-time editing a la Wave, PiratePad, or Gobi (or all of those other apps that I like so much).
What it does have is built-in support for custom CSS, support for Markdown, Textile, raw HTML or plain text, and a way to allow people to comment on your note (again, without signing in) by using a third party service called DISQUS.
Of course, there's an API, so you can easily create notes from your own services or embed notes into your own site. The whole thing feels incredibly well-thought-out. It's like the developer spent a lot of time pondering the question, "what's the least annoying and most open way to do this thing?"
Support multiple markup types, don't require logging in, provide an open API, and produce both a public URL (view only or comment if enabled) and an "admin" URL for editing your note as needed. It's all there!
Now, if it only had EtherPad-style editing, this thing could blow most existing notes solutions out of the water. Kudos!