AFAICT, this person is engaging in legitimate discussion in the threads he is posting in. Assuming there is not evidence this person has a history of these kinds of infractions, I don't think a ban would be appropriate. I would not want to remove someone from our community for a first time offense of this person breaking a rule that he may not be aware of.
I have sent this person a PM notifying him about the rules regarding having ads in posts, and that if he wishes, he can have ads in his signature.
In any case, it would be appropriate for the mods to remove the advertisement from this person's posts.