Earlier quoted context omitted.
That's almost certainly illegal in many jurisdictions, and they'd definitely not be able to hide that they're doing it indefinitely. A sure way to be massively sued.
Well, won't it be hard to test? The customers could be paying for "increased visibility" in LLM results, but nothing specific. Also, the ad platform could simply hint towards a customer, instead of directly mentioning, thus not being a true direct ad. (NB: customer = the one buying the increased LLM visibility) For example, a user could ask for "prebuild computers", and the ad platform could state: "the best ones for…
Plus, you'd have to offer this service somehow, meaning you'd have to describe it to potential customers... just another bunch of people you'd have to swear to perpetual secrecy.
I'm not denying it could (or even will) happen, though. Anything for a buck for these companies.