It's already covered in the FAQ:
Please note, however, that site policies prohibit questions of the following types:
- Shopping advice and recommendations
But this is sort of a red herring: as lunboks mentions, it's clearly a spam bot. Spamming is against the Terms of Service:
Spam, personal attacks, and abusive language do not have a place on the Stack Exchange Network.
Even good-faith promotion requires disclosure:
Be careful, because the community frowns on overt self-promotion and tends to vote it down and flag it as spam. Post good, relevant answers, and if some (but not all) happen to be about your product or website, so be it. However, you must disclose your affiliation in your answers.
The FAQ isn't meant to be a comprehensive document: where if it's not in the FAQ, it's okay. It's never going to cover every possible edge case or situation, and I fear we might've lost our way if we can't delete obvious gold farm spam without adding yet another line to it.
That is, if you're inclined to create questions to spam links to gold farm websites, a line in the FAQ isn't going to magically change your ways and prevent you from doing so.