According to Wang's initial study, more than half of users reused the same password from site to site or modified it slightly.
“It is difficult for humans to memorize unique passwords for the 150+ accounts the average person has,“ Wang said in a statement. “Inevitably, people reuse or slightly modify them, which is a dangerous practice. This danger has been amplified by the massive data breaches which have given attackers more effective tools for guessing and hacking passwords.”