'I love you' was an email message that people were delighted to receive. It was sent to thousands of people on the morning of 4 May 2000. But it contained a virus! When they opened the email, the virus went to everyone in their address book. It quickly spread around the world, and caused terrible damage to hundreds of computer systems. Most large organisations, including the British government, had to close their email systems to get rid of it. A Filipino computer programmer had written the virus. The police arrested him, but at that time it wasn't a crime to write computer viruses, so they had to let him go.