An algorithm that processes private user data is by itself not invading anyone's privacy. It's clear to me that invasion of privacy only happens when humans look at private user data directly, or look at user data that's not sufficiently processed by an algorithm.

Otherwise, something as simple as a spell checker would be an invasion of privacy because it literally looks at every word in an email you write. That's absurd.

I think there was a case, where several people loged in the same Gmail account and shared data not by sending mails, just by write and read drafts.

Companies are legally obligated to scan for CSAM in the US.

Pre-AI we had a system that watched user patterns and would identify possibly suspect patterns that were outside of the norm. We also had system that would content-id the images and attachments to see what was going uploaded in a general way. Given enough suspicion then the account would be opened to look for abusive patterns.

There is absolutely no promise on any cloud hosted services that a human will not ever see your data. However, at Google it was made very, very, VERY clear that if we had to scan somebody's personal email for any reason then discussion of the contents outside of legally mandated, or required for work ways would lead to immediate termination and possible lawsuit for any damages to reputation incurred.

While fixing user accounts, or dealing with delivery of content I saw epic piles of personal email. Besides the ones full of CASM or other abusive material I couldn't say that I ever remembered the contents 30 minutes later. Its like a checker at a grocery store. They don't care about whatever embarrassing tings your buying and won't remember you 10 minutes later. =)