Youtube mostly suggests already seen videos, hence i wouldn't classify it as a good recommender. I agree with your comment on instagram. In general, there are

Youtube mostly suggests already seen videos, hence i wouldn't classify it as a good recommender. I agree with your comment on instagram. In general, there are multiple approaches on recommender systems, to name but a few: -suggest content with similar features with what you watched -suggest content that similar users already watched -suggest completely new and/or different content I haven't used tik tok, but you might fall into category #2 and #3. And to be honest, if i owned such an app i would pursue users to be recommended new and popular content to keep them in the platform.