It turns out that most people get a lot of notifications about other peoples’ posts, and the only reason they visit Facebook at all is to see them! So if you haven’t been posting pictures or videos lately, then no one really has any reason to come by.
Now there is a common misconception that Facebook likes are shallow and not meaningful, but the fact of the matter is that their meaning cannot be overridden by any individual. If you don’t like something on Facebook, or if you delete your account, the importance of those likes doesn’t go anywhere. They are still recorded in history and will have consequences for future generations.
So liking something on Facebook is important because no one can go in and delete their likes, so the fact that people like Trump means that there will be policy consequences. The same thing can be said for any public figure or place. For example if enough people liked a particular restaurant then it would stay open.
Likes are also important as a personal motivator. If you like something on Facebook then it is likely that you will continue to do so, and if there are consequences for liking something than those consequences can motivate people to act in particular ways.