1. A computer program product embodied in a computer-readable medium, the computer program product comprising an algorithm adapted to effectuate a method for reputation management, the method comprising: receiving a plurality of ratings, wherein each rating is associated with a service provider and a rater; modeling the service providers, the raters, and the ratings as a factor graph representing the factorization of a joint probability distribution function of variables; wherein each factor node corresponds to a rater and is associated with a local function representing marginal distributions of a subset of the variables, the subset comprising a trustworthiness value associated with the rater and one or more ratings associated with the rater; wherein each variable node corresponds to a service provider and the service provider is associated with a reputation value; calculating the marginal distributions using a belief propagation algorithm applied to the factor graph; and determining reputation values associated with the service providers and trustworthiness values associated with the raters based on the calculating.