Bingo. In the case of the SB terrorists, the FBI could have used the already open social media platform Twitter to find these terrorists *before* they struck. The government is more obsessed with knowing every private thought of every person than they are with actually catching terrorists.
One might also wonder about the competency of the FBI in the SB terrorist case as this agency didn't bother to secure the apartment of the terrorists, which was latter compromised evidence-wise by reporters.
The NSA spies on their enemies, not our enemies.