In the ongoing Viacom / YouTube debate the judge (district of lower new york, i'm sorry to say) has mandated that youtube turns over its user logs to viacom so they can mine the data to try to prove some DMCA / copyright violations in the way that YouTube handled their data versus other video content.

Youtube tried to get the content aggregated / annonymized first, but lost that argument, and so, while email addresses will not be divulged, full screen names and IP addresses will. For people with fixed IP addresses, or those who use their full name as a screen name then their data has been wholesale surrendered, and as such this is a very scary president.

Luckily the judge held out on some demands, as at one point Viacom was asking for the source code to Youtube. This was deemed to be a trade secret and so was taken off the table.

Some blogs talk about what this all means here:

http://news.bbc.co.uk/2/hi/technology/7488009.stm
http://www.readwriteweb.com/archives/viacom_youtube_user_data.php
http://www.techcrunch.com/2008/07/03/judge-protects-youtubes-source-code-throws-users-to-the-wolves/