Attention bloggers high and low: if you allow me to make comments on your posts, you are entitled to mandate that I write them in whatever crazy moon format you choose: I’m comfortable with Markdown, Textile, or even the ordinary HTML that our ancestors used to use. But if you do not give me a preview button — so that I can make sure my comment looks the way I intended it to look; so that I am warned if you’ve arbitrarily decided to blacklist the blockquote element — I am entitled to reach through the Internet and strangle you.