Ads are typically not allowed in posts (outside of the signature area) because they are annoying and off-topic. It is especially disallowed to put ads or signatures at the bottom of all of your posts.
That seems crystal clear, but I'm not sure if Tao will be able to understand it.
EDIT: Sure enough, Tao is posting about how proud he is of his DashSpam. I knew he'd have difficulty understanding the anti-spam rules.