Traditional free-form stations prided themselves on offering their disc jockeys freedom to play significant music and make significant social commentary and humor. This approach developed commercial problems because disc jockeys attracted to this freedom often had tastes substantially different from the audience, and lost audience share. Also, freeform stations could lack predictability, and listeners' loyalty could then be put at risk. Progressive rock radio (not to be confused with the progressive rock music genre) was freeform in style but constrained so that some kind of rock music was what was always or almost always played.