Connection limits to CDN from naked domain might also be limited. Can anyone confirm ? Ex: if browser limit is 2 connections per host, bare + sub will only give 2 connections, while sub + sub will give 4 connections.

If you are using Websockets or AJAX the connection limit can become an issue.

Also some users always write www in front of the domain. Although some browsers will just redirect to Google. So if you check browser referer a lot will be from www.google.com?q=www.yourdomain.com