> Facebook and Twitter support a feature where quite literally users specify in no ambiguous term that they like something. It's not that simple. These feature

> Facebook and Twitter support a feature where quite literally users specify in no ambiguous term that they like something. It's not that simple. These features are also social. When you like a tweet on twitter, you send a notification to the author, and other people might see the tweet with something like "alice and bob liked this tweet". So you might decide to like or not to like a tweet for all these reasons. Youtube doesn't consider likes at all in the algorithm, only watchtime, even though likes are private in youtube, because it's too vulnerable to manipulation, to people telling you to "like and subscribe", etc..