Shifting Colloquiality

 Song "shopping" in the 90s sometimes involved submitting songs through TAXI, which apparently still exists. But if "song" and "songwriter" is now redefined, "shop" must also be redefined: what are we shopping for? What parts of the art are we shopping for (intros, outros, verses, choruses)? Who's buying what? These days I've fallen out of what the shopping experience is. In music I don't know