Heard the one about the common shampoo ingredient that causes cancer? Or how about the epidemic of blindness among toddlers who accidentally get waterproof sunscreen in their eyes? These absurd fictions used to be the stock-in-trade of ninth-graders bent on frightening the younger kids. But now such tall tales are appearing on the Internet, and many adults are taking them seriously.
Consider the latest electronic health scare: about the artificial sweetener aspartame, which is found in everything from Equal to Diet Coke. A widely disseminated e-mail by a "Nancy Markle" links aspartame to Alzheimer's, birth defects, brain cancer, diabetes, Gulf War...