Well, there are a lot of folks from companies like Ericsson and Cisco working on IETF's RTCWeb¹, so I guess they'll figure it out. And BitTorrent clients manage to do it, too.

¹ http://tools.ietf.org/wg/rtcweb/

Nope!

WebRTC has ICE/STUN built into it, which can suffice for traversing most domestic NATs.

It's really cool stuff - join the list!