In my personal experience, I first heard of it 1 year ago in a online forum game, people sold gold for Bitcoins, around March, gave it no importance at first. Now im kinda utterly commited to it. Really an interest subject of study.
Actually in 2010 i ignore bitcoin becuase the value is so much low so that's why im regreting when i always think about before, so first i heard about bitcoin is to my friend by the way he's a rich man now.