For example, the "relationship" status.
And it saves our blushes, a lot, by helping us promoting our "status".
Now, imagine this, your friend James just got hooked up with Betty last week, and facebook did not exist to tell you "James is in a relationship with Betty".
And you are in a bar with James, drinking.
You: You know Betty? She looks like a train wreck with lopsided boobies.
James: Yea, i do. We just got together, approximately a week ago. And her boobies are perfectly well formed.
It helps much more when you broke up. With the simple status of "James is single", everyone will know better than to rub it in. They won't go like this;
You: Hey James, where is Betty? I thought you guys were inseparable?
James: Oh, i thought so too. Until she found out last week that she likes girl better.
There are, of course, some people who never use facebook. Like you lovely grandma Mary.
Mary: Dearie, where is the sweet young thing that you brought here last time?
James: You mean Betty, Grammy?
Mary: Yes, that sweet girl.
James: Grammy, she decided that she likes girl more.
Mary: I don't understand...
James: She is now a lesbian.
Mary: Oh dear........