I would imagine each user has a copy of the other's messages in their own account, and that's what they would be hitting.
What happens when the law makes that illegal?
> What happens when the law makes that illegal?
just follow the Chinese model. complete blackout between the European Union, China and ROW. this is where this thing is headed, so we might as well start thinking about it.
People are acting like this is a trivial problem both technically & legally but it’s not. I don’t have sympathy for Facebook but if you are a small company handling data in the EU and other data outside it I have sympathy as it’s going to cost a lot in architectural complexity and compliance costs.
My GDPR compliance training said that data strictly necessary for the provision of a service is something a business can freely use to that end without explicit consent. This is why GitHub doesn’t show cookie popups: https://github.blog/2020-12-17-no-cookie-for-you/
So “User @Alice sent $message to user @Bob” is necessary for a chat platform, but “Notice to advertisers: User @Alice posts a lot about cars, cats, and funny shaped carrots” isn’t even though advertisers pay for the continued existence of the service.
A lot of communication data has two people associated, and a lot of it is highly sensitive. If a US person and a French person chat how does each get the messages? Message data is obviously highly sensitive and shouldn't be shared.
Does the US person need to hit the French servers to see new messages, and vice versa? What about quoting?
Message metadata (i.e. the fact that these two people are talking at all) is also pretty valuable -- the classic pen register is just a record of which calls were made to which numbers. Where do you store the metadata of the thread? It arguably belongs to and is private to both people.