Digg isn't the only major website to have forced users to remove a banned HD-DVD hex code: Google is doing it too.
On April 27, an unnamed user received a takedown notice from Google stating that one of his publicly-available Google Notebook pages contained material that infringed a copyright. The material? A sequence of hex codes used for decrypting HD-DVD movies. His notebook item linked to a Digg page covering the banned code.
Google's note stated that it would delete the user's entire notebook if the offending entry was not removed by April 30. Google also noted that it was doing this in compliance with the Digital Milennium Copyright Act, in response to a takedown notice it had received. Interestingly, the Google email stated that the notice they'd received would be posted to ChillingEffects.org. (The C&D notice appears to be this one.)
The user started a WordPress blog and posted the takedown notice, along with the offending code. As of today that blog is itself gone, with a note saying that the authors of the blog have deleted it. However, you can still see it in Google's cache -- for now. Was it removed in response to a takedown notice from WordPress? Let us know if you have information on this.
In the meantime, it appears that Google has not yet made good on its threat. The offending notebook page -- including the banned code -- is still online.