Cereal is everywhere these days. While diet trends come and go, those ubiquitous boxes and mascots seem here to stay -- and, in some cases, it seems people are buying an idea as much as buying a foodstuff. In part two of this two-part series, Ben, Noel and Max trace the brilliant, at-times Machiavellian marketing moves that led cereal to glory... and ask how long those days may last.