There's Peer5, which got acquired by Microsoft and got rebranded "ECDN": https://peer5.com/ https://peer5.com/ https://news.ycombinator.com/item?id=13501581 h

There's Peer5, which got acquired by Microsoft and got rebranded "ECDN": https://peer5.com/ https://peer5.com/ https://news.ycombinator.com/item?id=13501581 https://news.ycombinator.com/item?id=13501581 Launch HN: Peer5 (YC W17) – Serverless CDN https://www.ycombinator.com/companies/peer5 https://www.ycombinator.com/companies/peer5 P2P delivery network that enables high quality video streaming Also PeerCDN apparently, which got acquired by Yahoo? https://web.archive.org/web/20150810065820/https://peercdn.com/ https://web.archive.org/web/20150810065820/https://peercdn.c... If you run a Web search for some combination of "P2P", "Peer", and "WebRTC", combined with "CDN", you can also find a smattering of other (vaguely spammish) company blogs and (small, personal) GitHub libraries that seem to talk about something similar: https://www.w3.org/wiki/Networks/P2P_CDN https://www.w3.org/wiki/Networks/P2P_CDN https://github.com/AgustinSRG/webrtc-cdn https://github.com/AgustinSRG/webrtc-cdn https://mediafoundation.medium.com/the-rise-of-peer-assisted-cdns-how-media-peerpool-is-changing-the-game-6a84ae176908 https://mediafoundation.medium.com/the-rise-of-peer-assisted... https://github.com/vardius/peer-cdn https://github.com/vardius/peer-cdn https://www.cachefly.com/news/deciphering-p2p-the-basics-and-benefits-of-peer-to-peer-technology/ https://www.cachefly.com/news/deciphering-p2p-the-basics-and... https://castr.com/blog/ecdn-or-p2p-cdn/ https://castr.com/blog/ecdn-or-p2p-cdn/ https://github.com/Peer-to-Peer-CDN/P2P-CDN https://github.com/Peer-to-Peer-CDN/P2P-CDN https://blog.blazingcdn.com/en-us/next-generation-content-delivery-the-potential-of-p2p-cdns https://blog.blazingcdn.com/en-us/next-generation-content-de... So there appears to actually have been quite a bit of "concerted effort" in this direction, both open-source and with company funding. Either it's kept fizzling out for some reason, or became standard and is now taken for granted. IMO the most prominent project in this direction is PeerTube, in that it's using idle upstream bandwidth as a big part of its pitch (It's in the name!): https://en.wikipedia.org/wiki/WebTorrent https://en.wikipedia.org/wiki/WebTorrent https://en.wikipedia.org/wiki/PeerTube https://en.wikipedia.org/wiki/PeerTube https://news.ycombinator.com/item?id=38443855#38444796 https://news.ycombinator.com/item?id=38443855#38444796 (V6 dropped WebTorrent but still does "P2P via WebRTC".) But there are some privacy and security issues with this idea too. What happens if your website uses up all of a customer's data plan by uploading to peers when they leave it open in the background? And do you really want every webpage you visit to be NAT-hole-punching, announcing your presence, and uploading who-knows-what data to random strangers? A surveillance op could construct a list of everybody who visits a given page by simply refreshing the page every few seconds and logging the peers it connects to. And a vulnerability anywhere in the WebRTC stack, from router to browser, could let you get `pwn`ed by a random peer even if the website you visit is clean.