As this article in UK magazine "Computing" explains, the key is part of a battle over the future of digital rights management (DRM). Google now finds 297,000 references to this hexadecimal sequence, a key to unlocking certain copy protection systems.
The Advanced Access Content System (AACS) which developed the affected DRM system has been attempting to use legal strong arm techniques to prevent the distribution of this string. The result has been an enormous increase in attention to what otherwise would have been a minor matter ignored by almost everyone.
Digg has become ground zero for the conflict because it attempted to comply with the cease and desist order sent to them by AACS. But an enormous portion of the sites community began to repeatedly post and vote for the offending information, incensed by the imposition of their free speech rights. Finally, on the Digg blog, CEO Kevin Rose wrote that the community cannot survive if all of the members are at odds with the sites staff:
But now, after seeing hundreds of stories and reading thousands of comments, you’ve made it clear. You’d rather see Digg go down fighting than bow down to a bigger company. We hear you, and effective immediately we won’t delete stories or comments containing the code and will deal with whatever the consequences might be. If we lose, then what the hell, at least we died trying.This is an important day for the people's Internet. A company bowed to the possibility of an expensive lawsuit, testing first amendment rights of free speech. The company's customers then said "NO!" and forced the company to reverse course.
This kind of first amendment test has happened before. In an earlier case a math professor was pursued by the US government (under Clinton) for violating export controls when he wished to publish cryptography code on his website. Ultimately Daniel Bernstein won this case, with a federal panel determining that software source code is a language, and therefore export controls violated his first amendment rights.
This case is somewhat more complicated, in part because of the Digital Millenium Copyright Act. Here is a copy of the AACS complaint letter to Google. As the above link explains in the notes below the complaint, there is a substantial conflict between the first amendment and the DMCA:
The tension between the DMCA and the First Amendment is at the heart of several ongoing lawsuits. [Felten v. RIAA; Universal v. Corley] The mere posting of a link to a computer program that can be used to circumvent technical protection measures was held to be a violation of the DMCA. [Universal v. Corley (2d Ciruit cite)] The Recording Industry Association of America used the threat of a DMCA action to silence a professor whose research paper discussed circumvention of a technical protection measure. The professor subsequently mounted a legal challenge to the DMCA on First Amendment grounds and presented his paper. While courts in both of these cases have found in favor of the copyright industries, these cases are being appealed and the state of the law is yet to be determined.