> is made significantly easier to implement by web bundles. (Because with web bundles, the server doesn't need to understand the URLs at all) I agree it's a li

> is made significantly easier to implement by web bundles. (Because with web bundles, the server doesn't need to understand the URLs at all) I agree it's a little easier than what I described because there are no longer separate requests to connect, but it's not much easier. On the other hand, if you're going to give up on caching and bundle everything into one file you could just have your server inline the tracking script. (Or use HTTP2's server push.) Taking a step back, your last paragraph looks right to me. Ad scripts are very rarely served locally because there is an organization boundary between the ad network and the publisher (and a trust boundary), and they're large enough that you do really care about caching.