On the Internet, nobody knows you're a dog.

Interesting blog site: invisiblog.com. You mail in your posts via the Mixmaster anonymous remailer network; your blog's base URL is the fingerprint of the public key you use to sign your posts. Invisiblog.com can be forced (legally) to remove one of your posts or your whole blog, but they have no way of knowing who you are unless you're careless enough to let some identifying information slip into one of your posts.