In total, there were a mind-blowing 711 million records spread across numerous databases. That explains why Hunt found more than just email addresses among the data. He also discovered thousands of email/password combinations, complete with SMTP server (used for outgoing email) settings. Once that list has been assembled it gets pumped into a spambot, a computer program that automates the email distribution process. For example, Benkow discovered around 2 million Facebook addresses that were gathered by a phishing campaign.

Source: Forbes August 30, 2017 16:30 UTC