Gmail on the other hand has one of the best security track records in the industry, minus state-sponsored snooping (but that's a bit of a different issue, I think). There's zero instance of my Gmail mails being used by Google in anything other than algorithmic ad targeting.
Example: google “buy lawnmover” on your cellphone. Most likely other participants of the same LAN will sooner or later experience ads for lawnmovers. Now, google “Best online dating apps” or “im HIV positive how to protect my environment”, noone else than your own device, in limited scope, will see a followup-ads.
Or is that - just guessing here - considered too sensitive to share with the public?
I've spent my whole life sharing a wifi network with housemates, family, etc. and I've never once noticed this.
Gmail does btw