The Truth campaign launched in 1998, and over the next 20 years, may have reduced teen smoking by around 15%. Behind this massive PSA campaign are the tobacco companies themselves, who had to pay out over $200 billion in settlement money - under the condition that none of these campaigns would attack any tobacco company by name as part of the settlement.
One ad did, however, break this rule in 2001 - a commercial featuring a recorded phone call between a named tobacco company and a person wanting to sell them dog urine. The case was settled in 2006; the Truth Initiative won.