OK, so I'm not the most up to date or technical on deep packet inspection stuff and how Comcast (or any other ISP, for that matter) can snoop on what I'm doing if they like...
However, I'd imagine that if one were to change their DNS settings to use Google (or another free and open DNS service) and then use their Comcast connection to fire up a VPN connection to elsewhere, Comcast would have a really hard time telling what one was up to. Would this be correct? Would they still be able to tell what browser one was using?
Somewhere in all this mess, I have to believe that Comcast has better things to do with their time and resources. But I could always be wrong...
DNS requests are not encrypted unless tunneled through the VPN, tunnel, or whatever. Many people fail to properly proxy their DNS requests. So, yes, if DPI were used, Comcast would see DNS requests to Google just fine. I am not saying they are. Just hypothetically.