Neat concept, but browser sound support seems ... dodgy... Ipad: no sound; Firefox 24 on android: instant browser crash; Chrome on android: finally works.
Our focus in the next 2-3 months is on the desktop clients. We'll release a OSX desktop app next week, then a Windows app after that. Mobile is crucial in the long run but unfortunately we can't do much until the browser vendors provide better support for playing sounds.