After a performance I gave with musician and songwriter Pat Alger, he and I were asked a question about poetry and lyrics by a radio interviewer. Alger said, “A little poetry can really help a song. But too much poetry can sink a song.” Thinking about that statement I thought about song lyrics I like, where often a wonderful image is preceded and followed by “a shady lane” or “deep as the sea.” Sometimes, for some kinds of song lyrics, it seems that the water of ordinary language or even clichés, must be added to keep the mix from getting too rich.
Leaving that notion aside, the difference for me depends on how the cadences and melodies of language work without the element of performance. If it feels like poetry without requiring the skills of a performer or the ardor of the writer, then for me it is poetry.