This disclosure describes systems and methods for identifying and correcting anomalies in web graphs. A web graph is transformed into a set of weighted features. The set of weighted features are then transformed into a signature via a SimHash algorithm. The signature is compared to the signature of one or more other web graphs in order to determine similarity between web graphs. Actions are then carried out to remove anomalous web graphs and modify parameters governing web mapping in order to decrease the likelihood of future anomalous web graphs being built.