That’s not what I mean. What I mean is that Duolingo frequently comments on individual user posts on tiktok, which tiktok raises as a high-visibility comment because Duolingo’s size makes the algorithm think it’s quality content. This means that Duolingo isn’t just advertising on their own tiktok page, obviously that would be fine, it means that they get to piggyback on viral content from completely unaffiliated users massively spreading their brand while providing no compensation of any kind to the creator of those viral videos. It wouldn’t be okay for somebody to run an ad before your content without your consent (we aren’t talking about the ads you consented to run by tiktok/youtube/whoever), so it shouldn’t be okay to use the comments as free advertising space too.