wikiHow reports: "Collecting old debts - even debts for which you are not legally responsible - is becoming a very profitable venture. Companies can buy those debts (sometimes referred to as 'junk debt') for pennies to the dollar, then go after the people who they think are most likely to pay up. A phone call can turn into badgering, harassment, threats to sue, and other inappropriate (and sometimes illegal) actions. If you ever get a collector asking you to pay up on a debt that's 'come back to life', here's how to make sure your rights aren't violated."
I have some friends going through this right now, and here is a great article with how to deal with this type of harassment.