Do not be so sure at all.
You have an FB page, that means FB cookies on your machine.
You click on an FR thread to read it.
In displaying the FR thread, it goes off somewhere and runs some Javascript PROVIDED BY FACEBOOK!!!
The Javescript checks for a FB cookie on your machine, and records that you, as a user of Facebook, viewed FR thread XYZ on such and such a date and time.
May be it was a thread about not liking Obama. Maybe it was a thread about guns...
Get the picture?
Check my reply just above this. With Firefox and the right plugin, you can disable it.
I run Firefox No Script.
I have just received a number of emails sent from a business Blackberry from someone in China/Hong Kong which contained this person’s FB picture on it.
This is unbelievable.