Don’t fool yourself.
Gather information from those who do not communicate with one another. In fact, you want to gather information from entire networks that do not communicate with one another. Truly rich and diverse information comes only when you hear, separately and independently, from “worlds” that do not overlap: from different parts of the earth, different economic sectors, different social demographics, different religions, languages, ideologies and cultures.
via Think You're Well Connected? Stop Fooling Yourself.