1. A computer-implemented method, comprising: determining, by operation of one or more computer processors, the real-world identity of a first user of an avatar present in a virtual world; retrieving, based on the determined real-world identity, data describing at least one past criminal act of the first user, the determined real-world identity comprising at least one of a name of the first user and a physical address of the first user; determining, based on the at least one criminal act, at least one action to protect other users having avatars in the virtual world from potential harm caused by the first user; and performing the at least one action.