There's a few publications that don't even do that though and archive.is is very good at bypassing them so I do imagine they use logins for those, but for the masses of sites it's not currently necessary.
Sorry, but I wasn't. I thought that was clear from "can't afford the cost of keeping up-to-date with the Google IP list".
> They should have a great interest at blocking archive.is
Agreed, and many should have a budget to suit. So I conclude archive.is has put a lot of effort and cost into its defence. And all for free to us, the users.