About three months after I joined the Facebook, I still check Facebook regularly and post photos sometimes. Why do I do that? Because I would like to have a Like button for my self and want people to pay attention to me!
While a few people post negative comments and start fights on their facebook walls, most people casually click the Like button for the comments and photos. There are no Dislike or Hate buttons. You simply ignore the comment if you do not like it. And I can say most of us like the Like button.
Now think how often do you use the Like button in your life. I have to admit it is so easy to use the dislike button by complaining, nagging, and pointing out faults. If you would like somebody to change his/her behavior, you must recognize people; kids, spouses and coworkers, when they make good choices. Praising is a key factor but many people find it is extremely difficult to notice when somebody around them does good things. I hear people say when someone does a thing right that those people are just doing what they are supposed to do, why do I have to point it out or praise them.
Think about how Facebook is still growing. I think the Like button is the one of most powerful tools of the social network.