Most new FDA-approved medications are small, organic molecules , and the identification of a small molecule, or ligand, that binds a targeted protein with sufficient affinity is an early step in many drug discovery projects. This process involves considerable trial and error, and a typical drug discovery campaign project requires measuring the affinities of hundreds or thousands of compounds. Although the resulting binding data are essentially a by-product of an effort aimed at generating just a few potent binders, some of which will be advanced through the discovery pipeline, they are still extremely useful. First, data on the compounds that bind a given protein can inform the discovery of ligands for similar proteins. More interestingly, the aggregation of data from drug discovery projects spanning many protein targets has emergent value for a range of applications, including, for example: