I can not understand how my misdeeds during my college years can ruin my carrier or professional reputation. The career and reputation should not depend on certain facts about you kept secret. If something can ruin your career or reputation it should be publicly known. And definitely 'follies of the youth' do not fall into this category. As the BBC guy rightly said, our attitude towards the vast information we deem personal today will change in profound way. It is changing already today. For an amusing example see Snoopon.me.