Unlimited Edition

I was walking through town today and saw what was called a "limited edition" poster. What exactly does that mean? Is there such a thing as an unlimited edition poster? How could that happen? It reminds me of some traditional advertising phrases. My favorite is "fresh-picked," as in "made with fresh-picked vegetables." Well, of course the vegetables were fresh when they were picked. Or hearth-baked. Hearth, of course, meaning oven. Where else would you bake something?