This is a huge step forward for the javascript community. Having _real_ binary communication for WebGL games, media streaming, data analysis, etc etc is going to be huge.
For now the problem is consuming it. For instance, it seems Google still hasn't implemented a full API around the Audio object which could be used to flow wave data through your program. See here: http://code.google.com/p/chromium/issues/detail?id=113676... (and many other similar issues exist within the more advanced parts of the V8 JS arch runtime)
You can stream binary data through the Web Audio API to play it.
That bug is really for capturing audio, but the spec has substantially changed since that bug was filed. If you want to get started with it, there are several decent tutorials about WebRTC and getUserMedia out there...just keep in mind that the spec is still being written, so problems are to be expected.
(also, minor nit: WebRTC and the like are implemented in the browser (for Chrome, often at the Webkit level, but sometimes in Chrome itself), not in the Javascript engine. V8 is pretty isolated from those APIs)
Can't wait to see what people do with this.