It doesn't matter. The web is in Google's DNA, and facebook is a decent enough model to copy, from there they can just run on iterative improvements, which google excels at.<p>On a more philosophical note, Google is very much a social driven company. PageRank may seem like a wonky academic algorithm but it's a wonky academic algorithm designed to extract data from natural social human behavior (linking sites). That's a major factor of Google's success, they leverage the latent, <i>user-generated</i>, implicit data from hyperlinks as a source of explicit, tangible data. That very much conforms to social networking as well, taking data in human form (noisy, subtle, contradictory, and indirect) and making sense of it in machine form.