It used to mean a lot when you wished somebody happy birthday. It meant you had remembered.
Now all it means is that you have been reminded.
And when people are reminded to do something nice, more of them do it. And it’s lovely. But it’s harder to remember than be reminded.
Facebook doesn’t tell you that you haven’t kept a promise to visit a friend, or that you have forgotten about that person who you told yourself you would check on in a month’s time. But that doesn’t mean you can’t remember to do so.
And if you do, it will mean a lot.