- Skype, using P2P filesharing principles for telephony:
Zennström and Friis, the creators of KaZaa, one of the early and popular P2P filesharing systems, came up with the idea of using P2P to enable free phone calls on the internet, and Skype was born, poised for an extraordinary rapid update. Beyond phone calls, users have been creatively tinkering with it to enable audio and video broadcasts (i.e. Skypecasting). Excerpts from an interview in Business Week:
"Q: Where else could this go, beyond files and people?
A: It could be other resources -- you know, storage, video streams. But this really works on two levels. First there's the peer network, and I've been stressing that because it's the enabler for everything. But then there are the applications. We could not have foreseen -- wow! -- all the things that could be developed on top of P2P. For instance, when we first used peer-to-peer technology, we didn't foresee that we could do voice. It became obvious to us after some time, but when we started we didn't know what the applications would be. But when we applied the technology to various industries, we realized we could create a sustainable competitive advantage. That's because, in the normal system you have a marginal cost for every unit you add. If your network is client/server-based, you have to add a new network card for each new Web server, central switch, and so on. But in a peer-to-peer network, you're reusing the system resources in the network, so the marginal cost of producing a phone call or a file transfer or something else is zero. " (http://www.businessweek.com/magazine/content/04_44/b3906091_mz063.htm; http://www.businessweek.com/magazine/content/04_44/b3906087_mz063.htm)
An article explaining the rapid diffusion of Skype, at http://www.nytimes.com/2004/09/05/business/yourmoney/05tech.html?th
Open Source telephony developments for the enterprise market are summarized here at http://www.eweek.com/article2/0,1759,1823596,00.asp
PC to Phone services such as SkypeOut are reviewed by the New York Times, at http://www.nytimes.com/2005/09/01/technology/circuits/01basics.html?; Among the competing services it mentions are : www.gizmoproject.com, www.voicestick.com.
Google Talk vs. Skype VoIP, a comparison by Red Herring: http://www.redherring.com/Article.aspx?a=13339&hed=Is+Google+Talk+a+Skype+Killer%3f