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)

>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.

Fortunately this is changing with iOS 18 with "limited contacts" sharing.

https://mobiledevmemo.com/wp-content/uploads/2024/09/image.p...

The interface also seems specifically designed to push people to allow only a subset of contacts, rather than blindly clicking "allow all".

The far bigger issue is the contact info you share with online retailers. Scraping contact info through apps is very visible, drawing flak from the media and consumers. Most of the time all you get is a name (could be a nickname), and maybe some combination of phone/email/address, depending on how diligent the person in filling out all the fields. On the other hand placing any sort of order online requires you to provide your full name, address, phone number, and email address. You can also be reasonably certain that they're all accurate, because they're plausibly required for delivery/billing purposes. Such data can also be surreptitiously fed to data brokers behind the scenes, without an obvious "tiktok would like access to your contacts" modal.

On android you can choose whether to grant access to contacts. And most apps work fine without.

GrapheneOS, which I use, also has contact scopes, so troublesome apps that refuse to work without access will think they have full access. You can allow them to see no contacts or a small subset.

There's also multiple user profiles, a "private space", and a work profile (shelter) that you can install an app into, which can be completely isolated from your main profile, so no contacts.

It surprises me how far behind iOS is with this stuff. Recently I wanted to install a second instance of an app on my wife's iPhone so she could use multiple logins simultaneously, there didn't really seem to be a way to do it.

The point is that it doesn't matter whether YOU grant access to your contacts. As long as anyone who has you in THEIR contacts decides to just press "share contacts" with any app, you are doxxed and SkyNet is able to identify you for all practical purposes.