Yes indeedy, one must be careful.
I read in the current edition of Private Eye that The Mail website, "the most visited newspaper site in the UK", spies on it's staff and customers.
"For example, social media monitoring programme Radian 6, among other technology, helps to monitor Facebook and Twitter, as well as blogs, news sites, forums and videos to find out who is saying what about it's brands..."
Oops!

Ignorance is bliss, bliss is happiness, I am happy...to draw your attention to the possible connectivity in the foregoing.