Wastholm.com

The playkey, unlike the title folder, can't be copied—but it can be moved. To give your friends and family access to the file in question, you can send them a copy but must also provide a link to the playkey. Under the DPP system, though, anyone who can access the playkey can also decide to move it to their own digital vault—in essence, anyone can take the content from you, and you would no longer have access to the media files in question if they did so.