Stanford law professor Lawrence Lessig assesses Viacom’s chances against Google’s YouTube in a New York Times Op-Ed:

The Grokster case thus sent a clear message to lawyers everywhere: You get two bites at the copyright policy-making apple, one in Congress and one in the courts. But in Congress, you need hundreds of votes. In the courts, you need just five.

Viacom has now accepted this invitation from the Supreme Court. The core of its case centers on the “safe harbor” provision of the 1998 Digital Millennium Copyright Act. The provision, a compromise among a wide range of interests, was intended to protect copyright owners while making it possible for Internet businesses to avoid crippling copyright liability. As applied to YouTube, the provision immunizes the company from liability for material posted by its users, so long as it takes steps to remove infringing material soon after it is notified by the copyright owner.

Make Way for Copyright Chaos – New York Times, by Lawrence Lessig