There are tastes and behaviors exposed here that marketers ignore at their own peril. In years of studying these networks, both for anti-piracy projects and for marketers, The Jun Group says that one unmistakable pattern has emerged. "When a property is traded more on file-sharing networks, it sells more," says Mitchell Reichgut, CTO. "When it doesn't trade, it doesn't sell." P2P is not only a barometer of tastes but of media purchase-intent.

Whatever the worries over copyright infringement occurring on these networks, media companies continue to watch the P2P channel like a hawk, because they know that early adopters and trend-setters operate here. Jun Group operates on the Gnutella P2P network, which is dominated by the Limewire client software.

The company helps brands place media and marketing content like film trailers, free music and viral video into this ecosystem so that they show up as choices when users search for related material. Jun tells me that Limewire has been downloaded 180 million times, and some metrics find the client on one third of desktops. That translates into massive numbers of media searches -- 5 billion a month across all types of P2P networks, one survey found. "That is more than Yahoo and MSN searches combined," says Reichgut.

According to Jun principal Corey Weiner, young adults remain "the sweet spot" for P2P. "I would say 60% to 70% are between 13 and 34." And despite their reputation as havens for geeky boys, recent Quantcast stats suggest that 56% of the file traders are female.

That female demo is precisely what Kristen Colonna, Frito Lay Account Director at OMD, was after in distributing the "Only in a Woman's World" video series. The branded Webisodic features four women friends and their angst over diet and exercise.

"The digital platform was the key to staying connected and in the know," says Colonna, because the target audience uses the Web to find support from friends as well as information and entertainment. Along with multiple other video distribution platforms, she used Jun Group to seed the video into search results off  beauty, fashion and celebrity-related content. The series was not a commercial so much as a series of comic takes on the struggle to seem perfect, with Frito-Lay products featured as part of permissible indulgence.

While the P2P environment comes with certain hazards, Colonna says that it made sense to be there. "We're really seeing what we call the 'set it free' principle," she says. "We have been learning that with all of their fragmentation, people already know where they want to go [online.] You need to be where they are going. They consume it on their own terms. We need to be in as many places as we can and align ourselves with something bigger than ourselves."

Marketers are creating branded media like the "Woman's World" series, but too many just lap it onto YouTube and hope it goes viral, says Jun Group's Weiner. Leveraging the P2P channel works much like SEO. Jun has hundreds of thousands of connections into the Gnutella network, so it is seeing what people are searching for and can answer specific requests with a certain file. "We can make the content rise to the top of search," he says. "We will have a predetermined search term list so that whenever a term on it is sent out, we will reply with the videos." Back-end metrics can determine whether the video was played to middle or end and how often it was re-viewed. View-through stats can help the marketers understand whether the creative is appealing to users or if some optimization is needed.

It's hard to beat P2P as a content distribution vehicle, since some estimates show that a large share of all Internet bandwidth is actually being used for personal file-sharing. The most videos Jun ever delivered on a campaign so far approached 8 million downloads, but most campaigns that deliver over 1 million show up in the Visible Measure's viral video charts, and Jun claims this level of performance usually ranks them in the top 10% of campaigns for the year. 

Despite the scale, the real appeal of the P2P channel is the quality of the audience. These are the people who actively pursue digital content online. The recording and film industries may say they loathe the folks who seek out pirated copies of this weekend's blockbuster film release, or a leaked track from the next hip-hop sensation. In fact, though, these are the very entertainment junkies content companies need to watch and sell.