A client-server interactive television program guide system is provided. An interactive television program guide client is implemented on user television equipment. The interactive television program guide provides users with an opportunity to define expressions that are processed by the program guide server. The program guide server may provide program guide data, schedules reminders, schedules program recordings, and parentally locks programs based on the expressions. Users' viewing histories may be tracked. The program guide server may analyze the viewing histories and generates viewing recommendations, targets advertising, and collects program ratings information based on the viewing histories.