According to Ebay's Spring Update they're going to be banning all active content in listings in 2017 which I think includes links to youtube and websites.
Here's the quote:
"The use of active content in listings, including JavaScript, Flash, plug-ins and form actions, inhibits purchases on mobile devices and can lead to abuse in the marketplace. Beginning with the Spring 2017 Seller Update, eBay will limit the use of active content in all new listings across all devices and it will not be rendered by default. By the Fall Seller Update 2017, we plan to remove or block listings with active content. We encourage you to limit your use of active content now."