Great point Atma! If a friend of mine posts something of value, I'll probably upvote it, which helps out their reputation score. I do not upvote absolutely everything that a friend of mine posts though, or at least not a 100% upvote. That in itself creates that web of trust imo, since it shows that I am not a "yes man" and don't just agree with him/her because we are friends. True friends are encouraged to express their true opinions with one another. Now that friend knows for certain that they will always get the honest truth from me, even if it initially might feel hurtful. Trust is earned.