When telling a "Facebook fable", you're basically altering the truth. When asked by an old acquaintance or friend what you've been doing for the last few years, you realy don't want to admit that you've accomplished nothing of importance. Rather than telling what you've done, you tell the story the way you would have liked it all to be.
Jenny: Hey mate, it's been ages. How are you? What have you been up to for the last couple of years?
Bob:Hey Jenny. 'Oh, I dunno really, just doing this and that. Did some parachuting, jetskiing, travelled, did a year in the service and got myself a really hot grilfriend. You?
"In fact, Bob shat himself in the plane, refusing to get near the door of the little plane, went to the beach and watched other people on jetskis, left London to spend a day with his grandmother in Manchester, got kicked out of the army after a week 'cause he got high in the parkinglot and made out with a skanky 34-year old at the pub. He's told Jenny a Facebook Fable!"