Big problem: Facebook and others have refused to define what "terrorism" is.
Facebook has a fleet of low-paid contractors who are tasked with investigating possible connections with terrorism on it site.
The key takeaway: Moderators are granted "full access" to any account once it's been flagged by the social network's algorithms, which are looking for details or connections that might suggest a terror link. Moderators can track track a person's location and read their private messages.
The news comes from The Guardian, just days after Facebook chief executive Mark Zuckerberg announced the social network now has two billion users.
"The counter-terrorism unit has special clearance to carry out investigations into user accounts if they are suspected of having links to terrorist groups identified by the US State Department," says the report. "Moderators will then access the individual's private messages, see who they are talking to and what they are saying, and view where they have been."