Peer-to-Peer Comes Clean

They're not just for file-sharing anymore: P2P networks are transmitting phone calls, blocking spam, backing up hard drives, and spreading scholarship.

Despite ongoing efforts to blackball it, peer-to-peer technology is fast gaining ground. P2P gets its bad reputation for being the mechanism that powers those massive copyright-violation systems like Kazaa and Morpheus. But as I wrote a year ago in this space, this technology can be used for good: It has the power to strengthen the Internet against terrorist attack, allow even the smallest publishers to distribute information to the multitudes, and protect controversial information against censorship and suppression.

What I did not anticipate a year ago was that the most important peer-to-peer application to emerge in 2004 would be telephony. Yet that's what happened with Skype, the bandit Internet voice telephony system that has served more than 1.7 billion minutes of peer-to-peer telephone calls since its debut in August 2003.

But Skype is just one of several emerging peer-to-peer systems. Another is LionShare, a project started by Penn State University with a grant from the Mellon Foundation to create a series of networks for sharing scholarly information among academics. The system is designed to let individuals index and otherwise manage their personal files, then make these files available throughout a P2P network.

Many instructors, scholars, researchers, and librarians across higher education institutions have hidden' repositories of digital content used for teaching, research, and outreach stored on their networks or even individual hard drives, reads the LionShare grant proposal. The goal of LionShare is to open up this content into a federated search system so that a single search query [could] reach all available repositories, allowing academics to share photographs, sounds, instructional videos, and even PowerPoint presentations to a degree never before possible.

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Of course, professors could just put their materials on websites and let Google handle it all. But as anybody who has tried this knows, there is no easy way to specifically ask Google for contemporaneous photographs of Victorian houses in New England, authenticated by architectural experts, and available for royalty-free use in academic publications. The problem here is that Google does a lousy job with metadata and other kinds of catalog information--the sort of stuff that makes and breaks academic careers. LionShare will give researchers a tool for cataloging their own collections and then export those catalogs throughout academia.

There are a number of other potentially great P2P systems out there as well. BitTorrent, by Bram Cohen, is designed to let small software publishers distribute their wares to a large eager audience. Instead of hosting popular downloads on hugely expensive server farms, the idea of Bittorrent is to replicate popular downloads across hundreds or thousands of individually owned PCs. Think of it as Akamai for the little guy: in theory there shouldn't be any danger in copying files to multiple machines that you don't own, provided that every file is digitally signed. Unfortunately, it's beginning to look like the project has stalled. Still, the idea is fundamentally sound and it's sure to be extended in the coming years.