My use of Facebook has always been limited.
I didn't much care for the face mash premise of the original site, found the whole 'throwing sheep' era bizarre and except for a period where I auto-copied blog posts across, my use has been mainly as a backup for occasional marketing.
Recently I took a look at Facebook's own automated marketing aimed back at me.
They are far from the mark, deriving preferences for Daily Mail, Hong Kong English pop, Michael Flatley and Indian sanskrit voluntary organisations.
Maybe that's my price of erratic usage, or possibly it's as share-price-destroyingly bad with everyone else?