Harry Potter and the Order of the Phoenix launches today on DVD and HD-DVD. The HD-DVD consortium has revealed a new feature just for the HD-DVD release. This new feature ultilizes the standard network adapter included with every HD-DVD player. The gist of the feature is you can connect to a friends HD-DVD player and both of you can can simultaneously view the latest Harry Potter film fully synced up with message functionality.
From the official site:
Gather your own army of fellow wizards for a live community screening party. Invite other owners of the Harry Potter and the Order of the Phoenix HD DVD to simultaneously watch from their own internet-accessed players and text with your remote, PC or cell phone. When you host an invitation-only viewing, you control the film by pausing and playing the feature on everyone’s machine. You can chat live with your friends as you watch.
Now each session you create has a host and only the host can control the playback during the session. It isn’t said but is pretty much assumed that each party needs their own copy of the HD-DVD release for proper playback.