Doesn’t matter if you’re using an iPhone or android. They have your number, email, etc. (either given by you or by someone else when they uploaded their contacts to Facebook/instagram/whatsapp) and everything you do is tracked and logged.

That’s the thing about Meta. They gather info from literally billions of people, it doesn’t matter if you personally handed it over or not. Everyone who has your info — name, phone number, email, work number, etc. has probably already shared all or some of it with Meta. The moment you sign up and give them any info at all that matches your info in someone’s contacts, they’ll know it’s you.

If you don’t want them tracking you, your only option is to not use their services and block all their trackers. They’ll have your info anyway, but at least they won’t be able to track your activity.

Edit: a lot of people don’t grasp how bad the situation is with Meta. They trick people into uploading their contacts by requesting access to “help you find your friends” across their services, and they match that info and create a shadow profile for everyone. As soon as you sign up to any of their services, they’ll match that shadow profile to you. That’s why you immediately see people you know even though you just created an account. You’re in their contacts. Facebook has outed countless gay and trans people, as well as sex workers. They will also recommend your therapist’s clients to you as “people you may know” because you all have the therapist’s phone number.

It’s a nightmare. I’ve been trying to make people aware of it for like a decade or something like that. No one listens.

They can monitor you as much as they want. Your posts are the last of their interest.

Facebook trackers are very well spread on the internet, so your browser activity can definitely change what you will see in Threads.

Additionally, they monitor your view time, so they can feed you with contents that are more likely to attract your attention.

Finally, the information they got from your Instagram helps them create your home feed to fit your interests.

And only God knows what they can see through WhatsApp.

Ye, if you don't want to be tracked, then don't use Meta Services.

All of this, scroll down a bit to App Privacy and see that you have none. BTW, the "sensitive info" is racial, sexual and biometric data. Apps themselves are privacy-destroying, always look carefully at the app privacy. Check out the Mastodon app as a contrast, it wants none of your data.

Since you didn't specify and I don't know enough about Threads to say with certainty I'll assume you're logged in. At that point that's all that matters. Posting will only associate whatever you say with your account but ultimately your posting isn't exactly what they care about, they can monitor your traffic and usage in a number of other ways, especially if logged in.

A lot. The permissions that the app requires you to allow it should be a big clue that you are the product (as is the case with all Meta services and social media in general). If it wasn't designed to sell your data for various forms of tracking and ad targeting, regardless of how you use it, it arguably wouldn't need any special permissions at all.

@desmondjones this is a pretty useful article about the kinds of data the app collects :)
https://arstechnica.com/security/2023/07/how-threads-privacy-policy-compares-to-twitters-and-its-rivals/