Anne Petit considers research using social networks:
"If crazy people participate in social networks, what percentage of the world is crazy? Remember 500 MILLION people use facebook. 160 MILLION use habo. 130 MILLION use myspace. 80 MILLION use hi5. 65 MILLION use netlog. 70 MILLION use linkedin. And there are many more social networks with millions of users. These numbers are even more significant when you subtract from our 8 billion neighbours the people around the world who, as sad as this is, live in such wretched conditions that we would never consider marketing to them to begin with. Adding and subtracting all of these numbers means that possibly 50% of the world is crazy?"
Well, 50% seems low to me. Think of it: would a sane person buy a lot of what you see in either Nieman-Marcus or Wal-mart? A lot of the economy is crazy people buying crazy stuff. Selling crazy people stuff they don't need -- that's what marketing is all about!