A first user's trust level with regard to a second user can be determined by providing questions to the second user, with the questions based on a previously-collected knowledge base including information about the first user. The information about the first user may be partitioned into levels of trust, and the second user's responses to the questions may be evaluated to determine which level of trust the second user is entitled to. The knowledge base may be assembled by prompting the first user for information and/or by scanning or otherwise collecting already-existing data about the first user. The knowledge base and/or trust assessment may be distributed across a network, and in some embodiments the knowledge base or parts thereof is distributed to other users according to the trust level of those users.