Everyone knows your location: tracking myself down through in-app ads

One big privacy issue is that there is no sane way to protect your contact details from being sold, regardless of what you do.

As soon as your cousin clicks "Yes, I would like to share the entire contents of my contacts with you" when they launch TikTok your name, phone number, email etc are all in the crowd.

And I buy this stuff. Every time I need customer service and I'm getting stonewalled I just go onto a marketplace, find an exec and buy their details for pennies and call them up on their cellphone. (this is usually successful, but can backfire badly -- CashApp terminated my account for this shenanigans)

It is possible to just not use a phone number.

I mostly connect through Signal. I do technically have a phone number that my close friends and family have, but its a random VoIP number that I usually change every year or so. Surprisingly no one has really cared, I send out a text that I got a new number and that's that.

How? Most of the services I use, from Walgreens to banks to retirement accounts, require a phone number either for 2FA or just to verify that you’re you when signing up. After changing my phone number this year and having to go through the rigamarole for each service, I decided never again.