It's well known that tech companies track user activity. Facebook is one of those companies. It collects data from its own as well as third-party apps. Third-party app tracking depends on the number of services you connect to through Facebook.
See also: Americans trust Facebook and TikTok less than Google

What data does Facebook collect and how?
The data collected by Facebook includes users' screen time, various features they use, the number of times an app is opened, etc. In e-commerce apps, it has access to a user's purchase history, products listed, address and contact information, and more, as almost all of these apps have the "Facebook Pixel" code on their site and mobile app.
Facebook Pixel is an analytics tool that tracks your browsing, recording your identifier on the web. This data it collects is shared with Facebook. This is what allows it to display “targeted ads.”
Off-Facebook Activity feature
The “Off-Facebook Activity” feature is a relatively new feature that summarizes every action performed by a user on an external application or website. Applications and sites that use Facebook tools (Facebook login, share, FB pixel, etc.) share this data with it.
Even banking apps share user data with Facebook, through the Off-Facebook Activity feature.

The social networking platform claims that this summary of users' online activity helps it display accurate and targeted ads. In other words, apps you've signed up for using Facebook login are giving your data to Facebook to save you valuable time.
See also: Facebook: Will ask users if they agree to be tracked
What is more worrying is that Facebook may be creating a profile (through the information) for users who are not even on Facebook.
See how you can limit Facebook's access to your data by turning off Off-Facebook Activity.
There are two ways you can limit data sharing:
1. Stop tracking via the Facebook mobile app
- Open the Facebook app, click the three-line icon in the top right corner, and click “Settings & Privacy.”.
- Click on “Settings”.
- Scroll down and select “Off-Facebook Activity.”.
- Click the dotted line in the top right corner of your screen and tap “Manage future activity” (after tapping “more options” first).
- Turn off “Future off-Facebook activity.”.
2. Stop tracking via web browser
- Open Facebook in your browser and click on “Settings & Privacy” from the top right corner of your screen.
- Select “Settings”.
- Click on “Your Facebook Information” and then select “Off-Facebook Activity.”.

- Click on “Manage your off-Facebook activity.”.
- Select “Manage your future activity”, from the column on the right (“What you can do”, click “more options” and you will find it).
- Deactivate the option.

What does Facebook say?
Facebook says about the Off-Facebook Activity feature: “We get activity from businesses and organizations that use our business tools to better understand the performance of their website, app, or ads. We use your activity to show you relevant ads and suggest things you might be interested in.”
Although Facebook says it tracks activity to display personalized ads, many users criticize it about its practices and how it uses the data.
See also: WhatsApp: Finally you won't share all your data with Facebook
The most extreme but effective way to completely stop being tracked by Facebook is to delete your account and all its other applications (Messenger, WhatsApp, Instagram).
Source: Fossbytes
