Objective trust

Objective trust is sometimes used as synonym of reputation. In reality the trust cannot be defined objectively simply because every principal is free to express a level of trust in a certain trustee different from the level of trust expressed by the other principals on the same trustee. For this reason, it is better to use the term "reputation" when referring to an aggregated value computed by a global trust metric trying to represent what the community as a whole thinks about a certain principal. Of course different global trust metrics can compute different values of reputation for every principal and so not even the reputation can be called "objective" but simply an aggregation of the subjective trusts expressed by principals aggregated according to the characteristics of the global trust metric (simple majority vote, average, progation of trust on the social network, ...).

For example, Ebay and Pagerank are 2 global trust metrics that compute a single reputation value for every principal, but of course this is not the objective trust value since trust cannot be objective. In opposition, a local trust metric predicts personalized values of trust.