Trade goods like Aphrodisiac, Diplomatic Translators, Frictionless Clothing, etc, provide empire-wide bonuses to your civilization (or so it seems... I would sure hope it's not a bonus for just the planet they are built on hehe)
What happens when you trade them to other civs? Do they get the benefit of the trade good forever? Do you keep the benefit given by the trade good after you trade one? Do you have infinite copies of the trade good to trade out to multiple civs, or can you just trade it to one civ?