Christopher Mims:

His example was DDT, a pesticide and probable carcinogen that nonetheless saved the lives of hundreds of thousands of people in India as a cheap and effective malaria prevention. Today, we can see how one technology, Facebook groups, can serve as a lifeline for parents of children with rare diseases while also radicalizing political extremists.

Interesting set of rules, and the above is from the ‘technology is neither good nor bad, but both,’ section.