Hackers have struck one of the world's largest internet dating websites, leaking the highly sensitive sexual information of almost four million users onto the web. The stolen data reveals the sexual preferences of users, whether they're gay or straight, and even indicates which ones might be seeking extramarital affairs. In addition, the hackers have revealed email addresses, usernames, dates of birth, postal codes and unique internet addresses of users' computers. Channel 4 News has been investigating the cyber underworld, discovering which websites have been hacked and exposing the trade in personal information of millions of people through so-called "dark web"...