[cesarb]

> I don't think ISP caching would be a thing without https. It would bring a lot of additional complexity and resource requirements for them. I can hardly imagine that being worth it to save some bandwidth. Maybe it made sense in a world where bandwidth was very limited.

Transparent squid proxies were common back when most sites were on http. They let ISPs reduce the use of their limited upstream bandwidth, while also making sites load faster. The complexity and resource requirements were modest: install squid on a server, and configure the router to redirect (masquerade) all outgoing TCP port 80 connections to the port configured for squid on that server.

[blahaj]

The internet is much bigger, more diverse and complex today. You need a lot of storage to get any meaningful impact. Caching the http of Wikipedia won't get you much. You need to cache lots of YouTube videos. Or you just get them from the data center you peer with over the fat link you built.

With bandwidth usage the diversity of the data retrived over the internet has also gone up. You can't just cache the few most popular websites and save most bandwidth. But bandwidth capacity has scaled a lot so you probably also do not need to.