The information exposed can be particularly devastating to people living in small towns, where they are more easily identified.
For example, one person exposed in the hack is a 40-year old welder from a small Illinois town of a few thousand people.
He "will become anybody's slave" and lied about his age on the site, claiming to be 29.
Sexual issues dating site
No credit card data has yet been uncovered as part of the hack.
That data is incredibly revealing and potentially damaging.
Andrew Auernheimer, a controversial computer hacker who looked through the files, used Twitter to publicly identify Adult Friend Finder customers, including a Washington police academy commander, an FAA employee, a California state tax worker and a naval intelligence officer who supposedly tried to cheat on his wife.
Asked why he was doing this, Auernheimer said: "I went straight for government employees because they seem the easiest to shame." Millions of others remain unnamed for now, but anyone can open the files -- which remain freely available online.
That could allow anyone to extort Adult Friend Finder customers.
For instance, the security consultant Robb reported that one person whose information was hacked was a 62-year-old Hispanic male from New Jersey, who worked in advertising and has a preference for the "subporno" forum.
That, combined with his username and other account details, gave Robb enough information to Google him, find his real name, and find his social media pages.
Adult Friend Finder asks customers to detail their interests and, based on those criteria, matches people for sexual encounters.
The site, which boasts 64 million members, claims to have "helped millions of people find traditional partners, swinger groups, threesomes, and a variety of other alternative partners." The information Adult Friend Finder collects is extremely personal in nature.
When signing up for an account, customers must enter their gender, which gender they're interested in hooking up with and what kind of sexual situations they desire.
Suggestions Adult Friendfinder provides for the "tell others about yourself" field include, "I like my partners to tell me what to do in the bedroom," "I tend to be kinky" and "I'm willing to try some light bondage or blindfolds." The hack, which took place in March, was first uncovered by independent IT security consultant Bev Robb on her blog Teksecurity a month ago. It wasn't until this week, when England's Channel 4 News reported on the hack, that Adult Friend Finder was named as the victim.