The details of millions of users of Adult FriendFinder -- the dating site with the tagline "hookup, find sex or meet someone hot now" -- have been leaked by hackers. Channel 4 reports that details of nearly 4 million users were exposed on the dark web after a security breach.

As well as information such as names, email addresses, and dates of birth, hackers also gained access to personal information such as users' sexual preferences and details of their willingness to conduct extramarital affairs. The compromised data includes accounts that had been deleted by their owners, and the hackers are now threatening to hit out at victims.

No group or individual has yet claimed responsibility for the hack, but the data has been made available on a dark web forum. Security experts are warning that there is potential for users to be blackmailed by the hackers as it is thought they have the details of government and military personnel.

One of the people whose personal details has been published is Shaun Harper, who says:

The site seemed OK, but when I got into it I realised it wasn't really for me, I was looking for something longer term. But by that time I'd already given my information. You couldn't get into the site without handing over information. I deleted my account, so I thought the information had gone. These sites are meant to be secure.

The owner of the site, which has 63 million users all over the world, says that it has launched an investigation into what happened and is working with law enforcement agencies to get to the bottom of it. FriendFinder Networks Inc says: "We pledge to take the appropriate steps needed to protect our customers if they are affected".

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