Wired on Friday: While Google provides services for people looking for infringing copies of nude pictures, it also helps those who police copyright on the net, writes Danny O'Brien

The internet, so they say, is bad for the intermediary: the middlemen who normally sit between two individuals when they are conducting business or communicating. The internet, they say, promotes disintermediation - or cutting out the middleman - and allows data to flow with minimal mark-ups along the way.

Anyone wanting to step between sender and receiver better have a very good reason for being there, or else the market and the network will route around them.

But we're in a far more complex internet these days, and it's not always possible to see who are the middlemen, and who are those who we want to be able to stand between us and others.

Take a legal case that has just hit Google but has wider applications to many other search engines and web services. Google was sued by Perfect 10, a company which, like so many online, makes its money by offering subscribers access to pictures of women unencumbered with much clothing.

Some of their photographs appeared on Google's image search, and the company is suing for breach of copyright.

This sounds like one of those cases where the argument revolves around whether Google is allowed to make a sample of a copyrighted work without permission - "fair use" as it is called in US courts. In fact, the wrangle is more subtle. Google does not show samples of any of the nude pictures on Perfect 10's own website. Instead, Google's image search lists the same images on other sites - websites that are putting up Perfect 10's nudes illegally.

What Perfect 10 objects to is people inputting the names of their models and being presented with links to many pictures of those models, none of which are legal and none of which are Perfect 10's own site.

There is no way that Google could reasonably police the copyright of every image its search system uncovers online. Perfect 10 is arguing that Google is just as bad as the sites which pirate Perfect 10's photography, and wants damages from Google to reflect that.

It is an important case, because if Google is liable for such second-hand copyright infringement, it could be liable for millions of dollars in damages for dutifully recording every infringement or near-infringement online. The chances are that the courts won't go that far. The law is unsettled, and US courts tend to favour current business practices when faced with an ambiguity.

But not all cases like this have the backing of a billion dollar company. The same week, the Motion Picture Association of America (MPAA) announced it was launching suits against several BitTorrent indexing sites. BitTorrent is a piece of software that can be used to distribute movies and other large files - both legal and illegal.

BitTorrent's structure can seem a little convoluted. To download a particular large file, you need to find its corresponding torrent file online. The torrent file itself does not contain the final large file - torrent files are usually just a few kilobytes long - but it does provide clues on how to find the dozens of machines that each hold a part of the final file.

These several convoluted layers sound deceptive, but in fact they're simply part of how the BitTorrent system works, a system that's remarkably efficient at providing access to any large file with the minimum of cost.

For that reason the MPAA itself has publicly supported BitTorrent, and many Hollywood companies are looking into using it to legally distribute their content.

But many torrent files available on the web do not lead to legal files. They point to the pieces of pirated films, and to combat this, the MPAA has decided to go after certain torrent sites.

The sites they've picked do not host the final pirated movies. They often don't even contain the torrent files themselves. They merely provide web links to those torrent files. Like Google indexes the web, these sites provide indices to the world of files downloadable by the BitTorrent system

The MPAA claims these sites are as illegal as those who provide the movies or those who download them. And understandably, perhaps, the movie industry group intends to go after these relatively stable middlemen, rather than chase after the individual infringers.

The trouble will come when these two theories of how the law should work come together. If torrent sites can be fined for providing links to copyrighted material, shouldn't Google be liable for the same reason?

And if it's okay for Google to exist, how will the MPAA ever be able to catch up with the individual infringers? The answer probably lies within the functionality of these middlemen themselves. Google does not solely provide a service for people looking for infringing copies of nude pictures. It also allows companies like Perfect 10 to find exactly what websites are advertising and infringing on their copyright.

Moreover, just as these movie torrent sites guide those who want to download movies, so they can lead the MPAA to the very people who are intent on infringing their copyright. If they are intermediaries, they are intermediaries that can be used by everyone involved - including the court.

The internet has always had a way of either making the middlemen useful, or dropping them from the process entirely. Perhaps the law should do the same. There's no real reason why Google, or even those torrent sites, should bear the burden of defending themselves in law, when both can be used by copyright holders to hunt down the real infringers.