When an earthquake shook Los Angeles on March 17, the first news report wasn’t written by a human, it came from a program named Quakebot. This automated algorithm is just one of millions of tiny programs called bots that can do tasks faster on the Web than their human creators. From crunching data and patrolling websites, to making jokes and writing poetry, bots can be as humorous as they can be malicious. While their presence on the Web has raised fresh legal, ethical and privacy questions, bots are also shedding light on how companies personalize our experience on the Web. We explore the fascinating world of bots.