https://medium.com/forbes/facebook-investigates-how-messenger-app-was-used-in-russian-meddling-bcb9930525ba >By Kathleen Chaykowski >Facebook FB -0.03% Messenger recently emerged as one of a handful of major social media sites — along with Twitter TWTR -1.42%, YouTube , Facebook and its service Instagram — that were infiltrated by Russian-linked accounts to interfere with the U.S. presidential election.