Comment by jpc0
Food for thought that the parent didn't mention.
You will be unable to communicate except through face to face meetings. There is no more POTS(plain old telephone system), the entire world routes phone calls over the internet. There's no IM, the physical mail system will at least become dramatically backlogged if not fail entirely due to infrastructure failure internally and the new increased demand.
In my country is it not just that there isn't a POTS system, there isn't even copper. You have a FTTH(fiber to the home) link or a mobile connection. To my knowledge even in the US fiber terminates at the distribution point and your cable supply is last mile only.
I don't know what even will cause a global internet outage at the scale but it will be global panic.
> I don't know what even will cause a global internet outage at the scale but it will be global panic.
A coordinated attack on key infrastructure (eg: root DNS servers) could do it. Much of the internet is held together with duct tape and bubble gum. The reason it stays alive is because there are a lot of duct tape and bubble gum specialists :)
There are still a lot of ways to communicate without the internet over large distances (eg: radio, satellite, plane, drone, etc...) and there are different considerations/requirements for them. They are still an ultimate backup to the world we have created but shopping on Amazon via ham-radio would be quite painful!