This isn't a debauched wonderland of men cheating on their wives. It isn't even a sadscape of 31 million men competing to attract those 5.5 million women in the database. Instead, it's like a science fictional future where every woman on Earth is dead, and some Dilbert-like engineer has replaced them with badly-designed robots.
Those millions of Ashley Madison men were paying to hook up with women who appeared to have created profiles and then simply disappeared. Were they cobbled together by bots and bored admins, or just user debris? Whatever the answer, the more I examined those 5.5 million female profiles, the more obvious it became that none of them had ever talked to men on the site, or even used the site at all after creating a profile.
Then, three data fields changed everything. The first field, called mail_last_time, contained a timestamp indicating the last time a member checked the messages in their Ashley Madison inbox. If a person never checked their inbox, the field was blank. But even if they'd checked their messages only once, the field contained a date and time. About two-thirds of the men, or 20.2 million of them, had checked the messages in their accounts at least once. But only 1,492 women had ever checked their messages. It was a serious anomaly.