The web is evolving towards replacing the need for native apps. But it's going to need solid technologies and tools to do that. The Web Audio API is one of those technologies as it opens up a huge new realm of opportunities for developers.
Unlike other audio APIs, like WebRTC, Web Audio API is designed for applications that need low-latency and high-performance sound processing, audio editors, even audio creation tools or games.
Google Chrome already supports the Web Audio API and, to showcase what it's capable of, even at this early stage, Google teamed up with gskinner.com and came up with Technitone, a web app that enables users to create music in a visual way.
It has a simple interface, but it's rather capable since the instruments used can be customized to a high degree. It's a fun tool to play with, you may have some problems with it in some configurations, clipping, sound distortion and so on.