I'm not sure Frank Warren understood what he was unleashing in January, 2005, when he initiated his PostSecret project .

What started as something of a social experiment, encouraging people to send him their innermost secrets on a postcard, turned into something way beyond that.

It wasn't long before Frank, a mild-mannered man from suburban Washington, DC started receiving thousands of postcards, from all over the world .

In 2005 he published the first book. A collection of those postcards, called simply PostSecret. That's when I first met him.