Being tracked when logged off/on other sites is a bit different than shadow profiles.
Users are absolutely tracked when logged off or on other sites through 3rd party cookies, aka the Facebook Pixel. If you go on a news site that has the Facebook Pixel, it will record that you went on their site. When you go back on FB, they will check that FB Pixel cookie and see what other sites with that same cookie you've visited. Through that, they can compile a profile of what interests to use to advertise to you.
Shadow profiles are a bit of a different story, since that would essentially be FB compiling a profile of someone that has gone to all these sites with FB Pixel, but doesn't have a FB account. That's entirely possible, and would make it so that if you do eventually make an account with a FB-owned product, they've already got all of that info on you to start targeting ads.
The most low hanging fruit and directly impactful way to prevent this as a user:
1. Use a browser or browser extension that blocks 3rd party cookies
2. Use an email alias service like Firefox relay. This allows you to generate a random email address for every site you make an account on, and all those email addresses forward emails to your actual email.
Using the same email everywhere is essentially the same as what FB Pixel does, it allows all these sites to share with data brokers that bob@gmail.com has made accounts at these other websites.
3. This is a bit harder/not as cheap to do, but the same applies for using the same phone number when signing up to sites, it allows data brokers/ad networks to connect accounts across dif sites to the same person. If it's not required, don't provide a phone number.
If it is required and the number will be used to send important info, try to use a disposable phone number service that forwards to your personal phone number. If it's required but the number won't be used for important communication, use a fake number like 123-456-7890
100% agree with strategy #3, except I'm finding it harder to implement:
1. Everybody wants your phone number these days, especially those you don't want to give it to. From whatsapp and signal that use it as your main identify, whether you want to or not; to social sites like Facebook or Twitter that MAY let you sign up without phone, but "flag" you for security on first login and require phone; to other sites whether gmail or otherwise that require phone to sign in
2. More and more of them these days send a text to phone to verify it belongs to you
I'm therefore finding it harder and harder to not give my phone to everybody (of course, "not using the product" is always a possibility, so I still don't have a twitter account and by all accounts my life is better for it :)
For sure, though at the very least the examples you gave are mostly other social networks. So at worst, it allows them to know what other social networks you use.
What you want to avoid is using your phone number when doing things like online shopping, since that's when more personal details about you can be connected to your number, and therefore to the other social networks you used that number with.
> Being tracked when logged off/on other sites is a bit different than shadow profiles.
It all tastes like chicken. The tracking mechanisms are identical. You are probably given some "Ad ID". And that Ad ID correlates with your facebook ID if you have a facebook account.
Calling it a "shadow profile" sounds sinister. But its just commonplace tactics that any ad network is going to deploy. Facebook just happens to have more information on you than others.
Users are absolutely tracked when logged off or on other sites through 3rd party cookies, aka the Facebook Pixel. If you go on a news site that has the Facebook Pixel, it will record that you went on their site. When you go back on FB, they will check that FB Pixel cookie and see what other sites with that same cookie you've visited. Through that, they can compile a profile of what interests to use to advertise to you.
Shadow profiles are a bit of a different story, since that would essentially be FB compiling a profile of someone that has gone to all these sites with FB Pixel, but doesn't have a FB account. That's entirely possible, and would make it so that if you do eventually make an account with a FB-owned product, they've already got all of that info on you to start targeting ads.
The most low hanging fruit and directly impactful way to prevent this as a user:
1. Use a browser or browser extension that blocks 3rd party cookies
2. Use an email alias service like Firefox relay. This allows you to generate a random email address for every site you make an account on, and all those email addresses forward emails to your actual email.
Using the same email everywhere is essentially the same as what FB Pixel does, it allows all these sites to share with data brokers that bob@gmail.com has made accounts at these other websites.
3. This is a bit harder/not as cheap to do, but the same applies for using the same phone number when signing up to sites, it allows data brokers/ad networks to connect accounts across dif sites to the same person. If it's not required, don't provide a phone number.
If it is required and the number will be used to send important info, try to use a disposable phone number service that forwards to your personal phone number. If it's required but the number won't be used for important communication, use a fake number like 123-456-7890