The Internet is not so anonymous. Or, at least, YouTube isn't. Probably more to please those big media companies with wary eyes, YouTube has released the identities of several users that were pirating, including one fellow who was uploading television episodes before they had even aired. While that certainly won't stop the circulation of the videos, it very well demonstrates Google and YouTube's willingness to prove they are anti-piracy. This isn't the first time they have done this, either.
How will this impact YouTube in the future? It began as a very friendly site - open, anonymous, quick. When people get scared of being exposed, whether or not they are pirating, their willingness to participate might shrivel up very quickly. When your entire business is based upon community submissions, it's important to keep them happy - and keep them feeling safe. Would you submit a video knowing that at any time they might send all they know about you to a probing legal authority?