(Currently using/testing the product). No, you don't shift anything to their servers. They give you a long/funky CNAME that you use for your www.foo.com DNS r

(Currently using/testing the product). No, you don't shift anything to their servers. They give you a long/funky CNAME that you use for your www.foo.com DNS record. So basically all your web traffic is going through their servers, and they "intelligently" cache static content and/or distribute it through a CDN. It works fairly well and is painless to deploy (mostly, had some minor issues at first).