Britain's Channel 4 first reported that Adult Friend Finder had been hacked on Thursday.
About 4 million users had information leaked in the breach, the network reported.
That said, given the nature of the sites affected, it has the potential to be compromising to some users if the data starts circulating widely.
In the aftermath of the Ashley Madison attack, numerous users reported receiving extortion and blackmail attempts.
In this incident, the users whose information may have been leaked won't just have to contend with the usual issues normally associated with a data breach (spam, hacked accounts, identity theft and exposed credit card info).
If a company gets breached or uses shoddy security practices, there's little users can do about it.
But you can mitigate the fallout by using a different, secure password for every site or service you have an account with, storing them with a password manager app if necessary.
The leaked information, which was listed in a number of spreadsheets, doesn't just include personally identifiable information; it also lists some of the users' more personal details, such as sexual preference, which users are open to having extramarital affairs, and which specific adult-oriented forums the user has been most active in.
Unfortunately for affected users, this incident isn't something that can be fixed with the cancellation of a credit card or a changed password. Today's increasingly interconnected environments pave the way for threats that will bank on systems' weaknesses for different forms of cybercrime.