WebTorrent

WebTorrent is a peer-to-peer (P2P) streaming torrent client written in JavaScript, from the same author of YouTube Instant, and the team at WebTorrent and on GitHub, for use in web browsers, as well as a WebTorrent Desktop stand alone version able to bridge WebTorrent and BitTorrent serverless networks.
History.
Before creating WebTorrent, the developers first created PeerCDN (content delivery network) which was bought by Yahoo! in 2013.
The idea behind WebTorrent is to make a BitTorrent-like protocol that works on the web browser, maintaining as much compatibility with BitTorrent as possible. Any web browser should be able to connect to a peer-to-peer swarm, fetch content, verify that it is correct, and display it to the user – all as much as possible without centralized servers relying on a network entirely of people's browsers. WebTorrent uses the same protocol as BitTorrent but uses a different transport layer. WebTorrent primarily relies on WebRTC connections, while BitTorrent uses TCP connections and UDP datagrams directly.
WebTorrent Desktop.
The WebTorrent Desktop bridges the two networks of WebRTC-based WebTorrent and TCP/UDP-based BitTorrent simultaneously. The BitTorrent client Vuze (formerly Azureus) less gracefully but adequately functionally incorporated WebTorrent adding simultaneous network bridging to their software. The developers used Electron that makes desktop apps using JavaScript with access to all the APIs from Chrome and Node.
Functionality.
Online video is the core focus as that is where WebTorrent is most useful. It is less suited for smaller files or data sets but is ideal for larger files.
File availability, as with BitTorrents, is dependent on torrent seeding. If few users are sharing a file a HTTP server providing webseeding would be the fall back. There is no sharing without webseeding. However, this could have some positive implications. Rather than using a middleman upload site to share a large private file with another person, with WebTorrent you may directly connect without leaving traces somewhere or potentially being archived on some upload site. You simply drag and drop your file to create a magnet link you may share with your friend. Connections are already encrypted but you may add extra layers of encryption with keys to send another way. RAM limits may be managed with IndexDB.
Adoption.
BitChute.
Launched in 2017, BitChute is a video hosting service that used WebTorrent P2P technology. It claimed in order to ease bandwidth issues of centralized streaming. According to Fredrick Brennan, there is little evidence BitChute actually uses peer to peer technology.
Brave.
Brave web browser and PopChest are "open source supporters" of WebTorrent, as displayed on WebTorrent's homepage.
Safari.
The Safari web browser is incorporating WebRTC and data channel support, as it is going to be in iOS 11, however, it will be requesting permissions from users for access to webcams according to rumours.