it's not how many chords you use but how you put melody into it and how it is arranged to be appealing that counts..You can even use 1 chord and still make a good song with different melodies..and for those saying that 4 or 3 chord songs are lousy songs..grow up or shut up! you don't know what you are saying...the human perception of music (non musicians and masses) can only accommodate a few chords and an octave plus 2 of notes which will register well for recall.. for the chord progressions, even if it is the same with a thousand of other songs, there are still unlimited ways to make variations such as melody, tone, tempo, groove, etc....yes it has been the long-used formula for pop music..but it doesn't matter if it's pop, progressive of whatever..good music from the heart is still good music...