Methods, systems, and apparatuses, including computer programs encoded on a computer storage medium, for cross-referencing comments. In one aspect, a method includes, identifying unstructured text in a document associated with a first product or provider, in the unstructured text, identifying, by the one or more computers, a reference to a second product or provider different from the first product or provider, determining a relationship between the first product or provider and the second product or provider based on content of the unstructured text, and providing an indication of the relationship for display on a document associated with the first product or provider or the second product or provider.