"Don't do or say anything you wouldn't want to read about on the front page of the New York Times," said the founder of Hustler magazine and owner of businesses that sell sexually explicit videos online.
               
It might be too late for many people who, lured by a supposed cloak of digital anonymity, have shared their innermost wishes, fetishes and fantasies on hook-up and porn sites. And those companies know that their digital troves of secrets are exactly what make them a target for emboldened hackers.
               
In exposing the Ashley Madison accounts of as many as 37 million users, hackers released a cache of potentially embarrassing and damaging data. The dump contained email addresses for U.S. government officials, UK civil servants, and workers at European and North American corporations, taking already deep-seated fears about Internet security and data protection to a new level.
               
"This represents a scary precedent" because of the scope and depth of intrusion into people's private lives, said Ajay Sood, Canada general manager at cyber security company FireEye/Mandiant. "Ashley Madison wasn't the first, but it's the one."
               
The data dump made good on the hackers' threat last month to leak customers' nude photos, sexual fantasies, names and credit card information from the Canadian website with the slogan, "Life is short. Have an affair."
               
The hackers, who have not been identified, appear to bear a grudge against the company and want to undermine it by exposing users to public scrutiny.
               
The prospect of attacks by non-financially driven hackers pursuing publicity, blackmail or moral judgments sends shivers through the online dating and sex industry.
               
Reports that blackmailers armed with the data dump are contacting Ashley Madison members for extortion will reinforce concerns.