Earlier quoted context omitted.
- What proxies are you using? - If you set up your own proxies: How do you handle the costs? - If you use someone elses proxy: How do you make sure they always work for your users? - Does you extension only proxy blocked traffic? How do you know what is blocked? Is there an official list?
I'm using Squid to serve proxies, albeit a modified Squid. On your 3rd point, it has a list, as well a manual activation button. It proxies only blocked traffic.
It feels like this will quickly become a game of cat and mouse with the block list managers.