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?
I hope webrtc does better with NAT.
For a P2P scenario it makes sense to have something like a chatroom.
Edit: Incase anyone is interested, I have a chat log up: http://ancarda.net/rtccopy.log.txt
I blogged about it back in 2009 anyhow (under the self-effacing title of "Opera is about to change the world?!"!).
Your example translates the file into a base64 string to send over the unreliable channel, which ends up being a pretty big performance hit compared to a native binary transport.
All of this is to say: WebRTC is getting there, but it's still going to be several months before it's ready for more than demos like this.
I wish developers would honestly stop doing that already. Capabilities and stability are far more important than a logo.
Firefox does have indexeddb, but if you want to do seek operations you're out of luck.
EDIT: To explain more, without seek writing dealing with large files is incredibly expensive, you have to write everything you've got to indexeddb every time you want to modify it.
-Data is transmitted here without encryption, directly to the other users in this WebRTC room. Use caution if sending sensitive files and communicate file passwords through a more secure channel.
"Your browser will likely crash if you attempt to send a single file larger than 100MB, your mileage will vary."