The International Fund for Animal Welfare is complaining about people selling items made from elephant ivory on eBay, arguing that such sales hurt elephant populations by encouraging poaching. That's almost certainly true, but only because of the current system of trade which criminalizes profit and ignores the property rights of people in countries to which elephants are native. The answer, as with the dwindling global population of other threatened species like the tiger, is to allow private ownership of wildlife resources. This will encourage sustainable harvesting and give owners the motivation necessary to keep poachers at bay. You can read all about this approach in a book by Ike Sugg and Urs Kreuter titled "Elephants and Ivory: Lessons from the Trade Ban," published by the Institute for Economic Affairs in London.