Google surely can draw a network of its ever-logged-in users just with their ad services alone: 1. You visit a page with some Google ad at home. 2. Someone el

Google surely can draw a network of its ever-logged-in users just with their ad services alone: 1. You visit a page with some Google ad at home. 2. Someone else at home visits another page with some Google ad. 3. Your browsers make the request through the same IP address, marking you as potential acquaintances. With the frequency of this happening, they can put weights on the edges to mark how closely you are related to that other person. And since they can, they will. Otherwise, it would be the loss of this great opportunity for them. I don't see Google being any less manipulative than Facebook, with all the capable tools they have now. They are ever-present, can track you almost regardless where you visit (ads and analytics), they can gather information about your profile/network, and most importantly, they curate the information presented to you (search and ads).