There's a famous New Yorker cartoon from 1993 that shows a dog sitting at a computer screen saying to another dog 'On the internet nobody knows you're a dog'.
Because there are people online who concoct intricate stories about fake illnesses and tragedy. They research medical conditions, buy equipment to fake photos, and invent a whole community of followers.
All this can be done so convincingly that it encourages other real people to join in. And the people behind the hoaxes don't necessarily do all this for any financial gain, but for the sympathy and attention it gets them.
Rachel Monroe talks to This Way Up's Simon Morton about how technology enables these hoaxes, the ethical dilemmas facing people committed to stopping them, and the phenomenon of 'Munchausen's by internet'.