Thanks to the paranoia of moviemakers and broadcasters, American televisions are encumbered with a technology called the broadcast flag. A signal sent by the broadcaster can tell a recording device such as a DVR that the program being shown cannot be recorded at all, or can only be kept for a limited time.

This week, the broadcast flag reared its ugly head when Windows Media Center users found that they couldn't record some shows on NBC. Instead of seeing the recorded show, they saw a dialog telling them that "Restrictions set by the broadcaster and/or originator of the content prohibit recording." This was probably a bug in Windows Media Center software, because users of other DVRs such as TiVo didn't report similar restrictions.

It isn't the first time that the broadcast flag has been triggered, ostensibly by accident or software bugs. In 2005, the victims were TiVo users, who found that certain shows could not be permanently saved. That has been the sad story of broadcast flag usage; it seems to be more a bug than a feature.

In theory, the broadcast flag was a great solution for both Hollywood and broadcasters. Moviemakers were concerned, for example, that a HD broadcast of their movie might be grabbed by a DVR, keeping them from selling a DVD. Networks went along because they were concerned they might not be able to broadcast movies if Hollywood had concerns about "piracy." They no doubt had dreams of their own for the broadcast flag, like to prevent people from recording hot shows and skipping commercials.

Although Hollywood fought hard to get the broadcast flag wired into televisions, they haven't pulled the trigger on it for general broadcast content. That's a good thing; with every day that goes by, more people become attached to the convenience of DVRs. Five years ago it might have been possible for broadcasters to exercise their muscle and block recording of popular shows, for example, to appease advertisers who fear commercial-skipping. Today, they'd be facing a major revolt.

This whole broadcast flag thing is silly in a lot of ways. Tech-savvy users have easy ways to download high-quality movies and television shows -- illegally -- through file-sharing networks and torrent sites. Like so many technological "innovations" in DRM, what it really does is prevent rule-abiding consumers from enjoying and exercising fair use on legally obtained content.