With news this week of the messaging app being used to discuss war plans, we get you up to speed on what Signal should be used for—and what it shouldn’t.

Downloads of the app surged in the past week after the Atlantic published White House officials’ texts about a military strike.

Is the Signal messaging app really less secure than government systems? NBC News’ Kevin Collier explains Signal’s strengths and limits after an Atlantic magazine editor was accidentally added to a group chat where President Trump’s Cabinet officials discussed military plans.