That was the fearmongering, which made no sense because advertisers can't put a dollar value on "the AI will kind of sort of mention you", and because every conversation needs an ad. If ChatGPT always snuck in a brand mention even on the simplest questions, everyone would hate it.
Ad technology is really old. They're just going to use the same proven tech that has a track record of creating billionaires: intersperse content with sponsored blocks.