An Internet radio station program discovery service is provided. In general, the discovery service subscribes to or downloads a number of Internet radio station programs. For each radio station program, the discovery service analyzes audio content of the radio station program to dynamically categorize the radio station program over time. The discovery service also enables users to discover radio station programs of interest based on the dynamic categorizations of the radio station programs. The users may be enabled to search for radio station programs of interest based on the dynamic categorizations of the radio station programs, navigate or browse the radio station programs based on the dynamic categorizations of the radio station programs, or the like.