I used to work for Google and I can say that your assessment towards the end about search engines having the consumer far more in mind than a social network is pretty accurate. When choosing which results are shown to users it’s all about what’s most helpful and what’s most reputable. Google exalts sites which are beneficial to the user, no matter what the content of the website might be. As long as it’s relevant, valuable, and comes from a credible source, the information is fair game to be at the top of any search results.