Web Real-Time Communication (or WebRTC) is the open standard browsers use to send audio, video, and data straight to each other. There's no plugin or native app, nothing beyond an API that every browser already ships. WebRTC covers the media path: once two peers have found each other, everything from codec negotiation to encoding to transport is handled. What it never covers is the finding part. This article discusses the three APIs that make up the spec, why signaling and NAT traversal li...