Back in 1998, when the federal government unveiled a new batch of anti-drug ads, I noted that widespread experience with marijuana had made the anti-pot propagandist's job more difficult: People tend to be skeptical of tall tales about psychoactive substances when they themselves have tried those substances or know others who have without suffering any noticeable harm. That phenomenon, I suggested, "helps explain why government officials continue to insist that marijuana is either more dangerous than it used to be or more dangerous than we used to think." [read the full story here]