From Wired:

Google will have to turn over every record of every video watched by YouTube users, including users' names and IP addresses, to Viacom, which is suing Google for allowing clips of its copyright videos to appear on YouTube, a judge ruled Wednesday.

A number of questions arise about this: Why did the judge allow this massive violation of privacy; what will Viacom do with this information; why was Google tracking this? I think the answer to the latter two questions is obvious. To Google, it is a marketing goldmine. To Viacom, it may be proof that their copyrighted material was popular on YouTube, although that could established by other means. It could also be a marketing goldmine to Viacom. Google correctly that the data should not be disclosed because of the users’ privacy concerns. Of course, that works both ways. Google should not have accumulated that information because of users' privacy concerns.

This is big enough news that it made CNN. CNN gave it about 30 seconds, followed by several minutes about black actors portraying fictional US presidents. The EFF is getting involved.

This is a big potential privacy violation in the US and can lead to some interesting embarrassing moments (Maybe John McCain watches that dumb teenage lightsaber guy over and over). The real problem is in other countries. Now that the cat is out of the bag and every user has been tracked, will Google/Viacom turn information over to various governments about who watched what video that is illegal in their domain? Think that's not a possibility? Consider Yahoo and China.