Good tip.
I checked it but "close friends" is empty.
But you may be right.
Even though i don't interact on Facebook; i only check what videos/pics/news they shared and click the ones that i am interested in. (not even 'like' them)
But as you said, Facebook is probably tracking my 'clicked news/pics' and show those friends' activities.
I will monitor it for some time.
Thank you all for the tips.
Have a great weekend.