Also you asked in your article whether this can be used for ads.

Yes, there is an Israeli company offering to publishers to configure nginx as a reverse-proxy ( https://vip.wordpress.com/plugins/yavli/ ) and they serve the ads as small chunks of images (to not match the usual 300x250 or 468x60).

It made Easylist quite angry at the time: https://easylist.to/2015/08/19/issues-with-yavli-advertising...