YouTube defends itself against Viacom's persistent legal action over copyright:
For years, Viacom continuously and secretly uploaded its content to YouTube, even while publicly complaining about its presence there. It hired no fewer than 18 different marketing agencies to upload its content to the site. It deliberately "roughed up" the videos to make them look stolen or leaked. It opened YouTube accounts using phony email addresses. It even sent employees to Kinko's to upload clips from computers that couldn't be traced to Viacom. And in an effort to promote its own shows, as a matter of company policy Viacom routinely left up clips from shows that had been uploaded to YouTube by ordinary users.
Viacom's efforts to disguise its promotional use of YouTube worked so well that even its own employees could not keep track of everything it was posting or leaving up on the site. As a result, on countless occasions Viacom demanded the removal of clips that it had uploaded to YouTube, only to return later to sheepishly ask for their reinstatement. In fact, some of the very clips that Viacom is suing us over were actually uploaded by Viacom itself.
(Hat tip: Kottke)