Samboy needed to re-launch their iconic brand of chips back onto the Australian market after years in the wilderness under foreign ownership.  One of their promotions involved a $10,000 prize for the person getting the most users into a Facebook group with "Samboy is Back" in the title. Nothing particularly ground-breaking there really, but something happened that Samboy or their PR team probably didn't count on.  They got hijacked by Kimberley Evans, a Facebook user and Samboy fan who found an easy way to motivate a group of followers - by being self-less.  Her group was titled;

Samboy is Back - JOIN NOW TO WIN $10,000 FOR THE RED CROSS BUSHFIRE APPEAL

In seven days, Kimberley's group went from zero to 120,000 members and easily took out the competition.     The lesson here is that social media is never going to be predictable, and there's just no telling what your audience is going to do with your stuff once you've  put it out there.   Sometimes though - it will be simply remarkable.