Thanks for your clarification.
As far as his link to his own page, my understanding is that this should be allowed in direct response to questions. Perhaps I'm wrong. Perhaps he should only post a link in this thread to his advertising post (which is allowed). Or perhaps I'm completely wrong and he shouldn't be allowed to post anything related to his product in this thread. however I'm not going to be the judge of that.
Yep.
But even if it isn't against the rules, its basic etiquette not to spam advertising.
He wasn't answering a question but advertising his product to someone who was providing constructive criticism.