The manhunt is ongoing.

Officers in Boston are going door to door, searching for the second suspect in the Boston Marathon bombing. He is at large and believed to be armed and dangerous. The first suspect is dead. Residents in the area have been urged to stay indoors.

This dramatic turn of events took place shortly after the FBI released to the public additional photos and videos of the suspects at the site of the blasts that killed three people and wounded 180 people.

What role did social media play in tracking down the suspects? To what degree was the FBI investigation crowdsourced? And what have we learned about the suspects from their own digital footprints on various social media channels?

Earlier this week on News Stream, I talked to our regular contributor and NewYorker.com editor Nicholas Thompson about the role technology and social media has played - from disaster communications to offering help to the victims to communing during a time of senseless tragedy.

But given events in the last few hours, it's a conversation that begs to be revisited.