It wouldn't take much for a search engine to tip public opinion. One study, published in the Proceedings of the National Academy of Sciences, attempted to simulate the workings of Google [...] the authors kept reordering search results and then asking respondents to divulge their opinions. Placement in the search engine, it turns out, matters a lot: "On all measures, opinions shifted in the direction of the candidate who was favored in the rankings. Trust, liking and voting preferences all shifted predictably."