I hope to post some samples of networking in the coming months; right now we are just trying to get people started with basic functionality (and I apologise for the lack of samples so far...). Basically though if you are familiar with AJAX-style programming for HTML, you should have no problems writing networking code for HD DVD since the same principals apply. Do you have access to the HD DVD specifications? The APIs for networking are available in Annex Z.
You can never really know who your client is, although there are several things baked in to HD DVD that would prevent casual web browsing. For what purposes do you want to restrict access only to HD DVD players?
I guess the only reason I could think of to restrict content is the perception of a "value add" with the purchase of an HD DVD disc. Meaning, if you only want purchasers/renters of a HD DVD title to be able to access special stuff that's downloaded, etc.
Thanks for the reply, Peter!
-Robert
Probably a better idea would be to allow both web browsing as well as enabling HD-DVD players to download the added clips or special features. They can simply provide a special access code with the HD-DVD disc, so whoever buys it can go to the website and download the stuff.
My guess for restrictive access to HD-DVD players would be for firmware upgrade. If anyone needs to upgrade the firmware for their HD-DVD players they can simply hook up the player and download the content. However, same reasoning as above can be applied to this as well for web-enabled access.