Reuters is reporting that Viacom, the parent company of MTV Networks, whose Comedy Central unit produces The Daily Show and South Park, among others, has retracted its agreement with Google's YouTube unit reached last October, and is asking Google to remove videos of programming it produces from public access.

Relations between the two organizations have been shaky since May 2005, when Viacom Corp. issued a subpoena to YouTube (which was then not owned by Google) asking it to remove extended clips of the movie Twin Towers, produced by Viacom-owned Paramount Pictures. Last October, Viacom, Inc. had appeared to reach an agreement with YouTube that would have enabled it to carry clips of MTV Networks-produced shows.

Last September, YouTube reached a comprehensive agreement with Warner Music to stream music videos, though that deal doesn't extend to Time Warner and its studio holdings since Warner Music is no longer a Time Warner unit.

NBC Universal was one of the first major studios to strike an agreement with YouTube; and Universal Music (no longer a member of the Universal family) forged an agreement last October that ended what could have been an ugly spat with YouTube.

But last month, 20th Century-Fox filed suit against YouTube in a court in California, in an attempt to have the site remove clips or entire episodes from 24 and The Simpsons, which the company produces and which appear on the Fox TV network.

The latest wave of bad news comes as Google rolls out a new feature this month enabling users of its Orkut social community site to share YouTube playlists with one another.