Knock knock, who is it? Wouldn't it be nice to know who is on the other side of the door? Now, you can, with a smart doorbell you are able to see who it there, speak to them, and for your safety, record who crosses your front door. Instead of trusting someone saying they are the police, you can verify who is really there. Don't forget, you can catch all those falling down the stairs clips and send them to America's Funniest Home Videos!