I think it's not really advisable to do that, for privacy reasons:

https://news.ycombinator.com/item?id=9112717

https://news.ycombinator.com/item?id=9893561

Also your CDN'ing clients could serve different content, giving some of your visitors a random surprise...

You can easily avoid "surprise" by hashing content, but malicious clients still will be able to delay content load.

you can authenticate the content to prevent that

Yep you can. There was this http://peercdn.com/ that did that and I remember a post on HN where it served the page from other clients but used web sockets instead.

>This page exists only if someone is looking at it

https://news.ycombinator.com/item?id=9531265