Not forgetting massive variations across nations.  A company I used to work with did some FB advertising, targeting nations they did good business with via Adwords.<p>UK and USA were the worst for clicks, the rest of Europe a little higher, and apparently in the Far East everyone clicks everything multiple times.  Click through rates were ridiculous.<p>Also interesting to note that despite being online and profitable for yearss they never did find a way of making Facebook pay, in any nation.<p>We never did make sense of it!