Matrices, Compression, Learning Curves: formulation, and the GROUPNTEACH algorithms.
GNT takes a collection of facts, arranged in a binary matrix, and reorders the rows and columns for the purpose of teaching and visualization.

BIRDNEST: Bayesian Inference for Ratings-Fraud Detection
BIRDNEST is an algorithm for detecting fraudulent users in timestamped ratings data (e.g. users ratings products with 1 to 5 stars), based on detecting users that differ excessively from the norm, in terms of what ratings they give and the time distribution of their ratings.

FRAUDAR: Bounding Graph Fraud in the Face of Camouflage.
FRAUDAR is an algorithm for detecting graph fraud based on dense subgraph detection, which is aimed at being robust to camouflage (i.e. attackers which add false edges in order to mask their presence)