These are usually in response to a complaining post. These people think that they're leaving a supportive remark that will help their discontent "friend." There is a flaw in this logic, and exposes this "friend" for what they truly are. Let's look at the difference between a real friend and a "facebook" friend, shall we?
The first difference is this:
A facebook friend doesn't tell you the truth, but a real friend does. A real friend is concerned for your well being above that of your feelings, and tells the truth in love. If they think you're doing something that may bring harm to you or someone you love, a real friend can't stand to see you travel down that path.
Another difference is that when you are harming yourself, your friend will feel that pain as well. They won't leave a one sentence remark, but they truly experience your pain, though maybe not as acutely as you do, with you.
Also, a real friend doesn't attempt to appease your pride, but recognizes that we all must consider others' happiness, and we must do so before our own. You see, we are all concerned when others don't care about our happiness, so let us care about the happiness of others.
In closing your real friends will: tell the truth which includes things you don't want to hear it, stand beside you, physically and emotionally, carrying your burden with you, and they will encourage you to love others' more than yourself, to treat them better than you would like to be treated! Most importantly, your friend will build you up in your relationship with the Lord. If spending time with someone, in reality or virtually, causes your relationship with Christ to degrade at all that person is no friend to you.