There are already companies that do this for other thing. It's basically the model cloudflare uses, but they don't have the ad injection part. I believe brandin

There are already companies that do this for other thing. It's basically the model cloudflare uses, but they don't have the ad injection part. I believe brandingbrand did the same model for mobile sites. To the site owner, they're just pointing dns at the ad company and treating it like a cdn.