People who browse the web for medical information often cannot discriminate between scientifically valid information and quackery  Much of the quackery is particularly appealing to readers with no medical background because it is usually written more clearly than scientific papers
Thus, people who rely on the web when attempting to diagnose their medical conditions are likely to do themselves more harm than good
People attempting to diagnose their medical conditions will do themselves more harm than good only if they rely on quackery instead of scientifically valid information.