“PeerCDN automatically serves a site’s static resources (images, videos, and file downloads) over a peer-to-peer network made up of the visitors currently on the site. Offloading part of the web hosting burden to site visitors reduces bandwidth costs.”
The project also made a screencast to explain their approach – check it out:
PeerCND uses WebRTC’s data channel protocol, which was designed to allow developers of real-time communication applications to have their participants exchange data other than audio or video. Think of a file transfer during a teleconference, or a multiplayer game based on WebRTC. And in the case of PeerCDN, it sends files of a website directly from visitor to visitor.
The downside of this approach is that WebRTC is still in its infancy. The data channel protocol has been implemented in Chrome as well as nightlies of Firefox, which means that it will be available to the average Firefox user some time in the near future. Both browsers together “account for 58% of global browser usage,” as the PeerCDN site points out.
However, disputes around the way forward for WebRTC have complicated an implementation in Microsoft’s Internet Explorer, and there is no word yet from Apple whether it will support the technology in Safari. Still, site owners don’t necessarily need all of their visitors to buy in, especially since PeerCDN can be combined with a traditional CDN.
PeerCDN was built in part by Feross Aboukhadijeh, who is famous for some of his HTML5 exploits. Recently, Aboukhadijeh built a website that automatically filled up its visitors hard discs with gigabytes of cat pictures. Before that, he built a YouTube search site called YTInstant.