Brazilian (independent) Security and Behavior Research have Facebook Ticker that allows any person chasing you without your knowledge or consent. This tool – monitor others began to run when it introduced a new feature called Ticker. This new feature (Ticker) does not respect the privacy settings and it now Comments (updates), add friends, likes and can be seen by others (friend *) anyone without your permission. Nelson Novaes Neto, a Brazilian Security and behavior research have analyzed a privacy issue in Facebook.
Source: https://thehackernews.com/2011/10/how-facebook-ticker-exposing-your.html