Sharing is caring. If you care for people, you should share what you know with them. Somebody else shared his/her knowledge with you, so you should do the same. People give love, support, money and so forth. As we love getting, so we should love giving.
By giving we will make other people happy. When we teach what we learn, when we give what we get we will not only spread love, but surely make this world the better place we want to see.