One of the coolest implementations of WebRTC is a project my friend launched called PeerCDN (https://peercdn.com/) - basically allows you to reduce bandwidth costs by leveraging the resources of active users on your app.
With things like this, getting exposure isn't a matter of having the money to host your content, but simply a matter of being popular. The more popular you are, the more likely that you can offload static file hosting to those consuming your content.
My girlfriend brought up a good point: is there any way to opt-out of seeding?
Or maybe DOS your site, by pretending to be a PeerCDN participant but instead sending large chunks rate limited to 0.5Kb/s. The SHA1 hash check will stop them being used, but only after a long delay. People could be having a bad experience and you wouldn't even know by watching server stats.
How is the connection between peers encrypted?