[throwaway2990]

Of course I post on a throwaway. HN is full of idiots who downvote cos it goes against what they believe in.

Fact is Facebook has been advertising using user data on messenger and WhatsApp. Some believe it’s not possible and some theorise that they analysis the message on the device and send metadata over.

But it doesn’t change the fact Facebook is in control of the whole pipeline.

[zer0zzz]

You should have started with that, and added some sources (based on reversing, there are many out there). There’s a good claim to be made that even if they don’t use their app to wholesale decrypt chats locally, they do use metadata. Its likely they can’t do a good job of moderating without it.