I hate Facebook and never opened an account, but you can't escape data mining when you are on the net
https://steemit.com/privacy.html
Steemit, Inc Privacy Policy
Effective April 1, 2016
1We want you to understand how and why Steemit, Inc (“Steemit,” “we” or “us”) collects, uses, and shares information about you when you access and use Steemit’s websites, mobile apps, widgets, and other online products and services (collectively, the "Services") or when you otherwise interact with us.
True story