That's impressive and I'm glad it works for you. I don't generally sell many cars under £5k so we're not treading on each other's toes.
As of Aug 2013 (last published figures), approx one third of the population have active Facebook accounts. Which I admit is a lot.
But not as many as the two-thirds who haven't.
Hey, we can't be all things to all people, can we? What we do is find our position in the market and crack on.
Or, as matey from the DVLA would say, "Access your niche and exploit it"
And i'm more crunchy nut cornflakes than muesli