> If you browse through your smart TV, and the smart TV overlays an ad over the browser window, or to the side, is that the same as saying the original server i

> If you browse through your smart TV, and the smart TV overlays an ad over the browser window, or to the side, is that the same as saying the original server is serving those ads? I hope you agree it is not. I agree it is not. That is why I didn't say that the original server served ads, but that the _domain_ served ads. Without TLS you don't have authority over what your domain serves, with TLS you do (well, in the absence of rogue CAs, against which we have a somewhat good system in place). > If you use a web browser from a phone vendor who has a special Chromium build which inserts ads client-side in the browser, do you say that the server is serving those ads? Do you know that absolutely no browser vendors, including for low-cost phones, do this? This is simply a compromised device. > If your ISP requires you configure your browser to use their proxy service, and that proxy service can insert ads, do you say that the server is serving those ads? Are you absolutely sure no ISPs have this requirement? This is an ISP giving you instructions to compromise your device. > If you use a service where you can email it a URL and it emails you the PDF of the web site, with some advertising at the bottom of each page, do you say the original server is really the one serving those ads? No, in this case I am clearly no longer looking at the website, but asking a third-party to convey it to me with whatever changes it makes to it. > If you read my web site though archive.org, and archive.org has its "please donate to us" ad, do you really say that my site is serving those ads? No, archive.org is then serving an ad on their own domain, while simultaneously showing an archived version of your website, the correctness of which I have to trust archive.org for. > Is there any web site which you can guarantee it's impossible for any possible user, no matter the hardware or connection, to see ads which did not come from the original server as long as the server has TLS? I find that impossible to believe. Fair point. I should have said that I additionally expect the client device to be uncompromised, otherwise all odds are off anyway as your examples show. The implicit scenario I was talking about includes an end-user using an uncompromised device and putting your domain into their browsers URL bar or making a direct http connection to your domain in some other way.