This week, millions of people watched Obama's inauguration on the Internet through one of the many sites that offered a live feed. CNN's broadcast was without doubt one of the most used viewed streams, with a peak of more than a million simultaneous viewers and also one that was using P2P technology.

Despite the fact that there are thousands of legitimate uses for peer-to-peer technology, most businesses are not keen on using it because of the negative associated with it. One of the areas where P2P can really make a difference is with video streaming, either live or through sites like YouTube.

Offering a decent quality stream can quickly cost tens of thousands of dollars a month for medium sized sites, and millions of dollars for bandwidth hogs such as YouTube. So, why not share this burden and throw in some P2P? That’s probably what CNN thought too, as they offered a P2P supported live feed of Obama’s inauguration. With 25 million viewers on CNN.com, this was probably the largest P2P live stream ever, although CNN did not reveal how many people used the P2P plugin.

CNN has been working with the Denmark-based company Octoshape for a few months now. Users have to install the Octoshape plugin for their web-browser, and this makes the regular Flash player through which they view the stream, P2P compliant. This means that users who download the video partially to their computers also share it with others.

Thus far, CNN has not commented in public on their use of Octoshape’s P2P plugin. However, from an insider who’s familiar with the technology, TorrentFreak learned that approximately 30% of the bandwidth for CNN’s live stream comes from peers. This obviously results in a significant reduction in bandwidth costs for the broadcaster. The rest of the bandwidth still comes from central servers to ensure that there is enough available for everyone.

CNN’s live stream was only boosted by Octoshape for those who watched it through the default Flash player, not the Windows media stream. The Flash team from Adobe has been working on their own P2P Flash implementation for a while, but thus far we are not aware of any public tests of their technology.

It is interesting to see that CNN supports P2P based streaming solutions, even though it’s a shame that they went for a closed source solution, instead of an open source product. Last year, the Tribler team showcased their open source streaming application which relies solely on P2P, through BitTorrent. Tribler is currently working with several European TV-broadcasters to test this technology in the real world.

In theory, broadcasters can send a live stream to millions of people by only sending out the stream once, from a single server. With the current upload speeds and the throttling efforts by ISPs, this still only works in theory. Nevertheless, since more and more TV is being watched online, filesharing technology is the future.