This is about how search engines such as google and networking sites such as facebook select for us what we will see based on what we have clicked on before. It appears to me that this limits our exposure to novel ideas, and funnels us into thought tunnels, ie dogma. Interestingly, I receive political ads from every direction, perhaps because I have found good candidates on all sides. I click both ways. On many spectrums. I wonder what google and facebook are NOT showing me.