While I've been waiting for a service like this for a looong time (Get it in gear, iTunes!), I have a major problem with Movielink. It only works with Windows XP and the latest version of Internet Explorer.
Windows 2000, ME, 98, 95; Linux or Macs are not supported.
Standards-based Firefox or Opera browsers are not supported.
Great idea, but the bad implementation got them put on my public boycott list.