I wonder how it compares with Flotype's[1] Now: https://github.com/Flotype/now [1] YC W2011
WebRTC is a project building support for things like P2P and Device API support into modern browsers. This is so you could do things such as access a user's video camera through the Device API and establish a P2P stream with another browser, without using any Flash or installable plugins.
Now is just a JavaScript library that enables you to do RPC with browsers.