IPFS does not work in the browser yet.
Disclaimer: I work at Protocol Labs on IPFS
Because both the parent post and the repo seems to indicate otherwise and the only reason I ask is because that sounds a little to amazing.
And thanks for working on this project!
go-ipfs, which I guess you refer to with the mainstream network, has support for websockets which the browser nodes has support for as well, so they can interop.
So it is not great, but does work. WebTorrent is also WebRTC fyi.
The tech isn't quite there yet, but eventually yes everyone's machine could be a CDN of sorts.