Anonymous posts on Write.as
Anonymous posts are only identified by a secret, unique ID. Unlike posts connected to a blog, they aren't publicly connected to an identity unless you make it known in the post that you wrote it.
So, basically, this means I can publish standalone documents using Write.as that don't show up anywhere on my blog(s). I don't know how often I'll use this, but I like the idea. An anonymous post also works as a “draft” blog post. I write a post and “publish” it as anonymous and, when finished, move it to my blog.