What did one leaked password reveal about Mark Zuckerberg?

In 2012 hackers stole millions of LinkedIn passwords. Four years later the full haul, about 117 million accounts, turned up for sale online. Within weeks a group calling itself OurMine had taken over Mark Zuckerberg’s Twitter and Pinterest accounts. Twitter was one he hadn’t posted on since 2012. The group said it had found his password in the LinkedIn list: dadada.

It’s one of the most common habits a leak can reveal. In a 2014 study of several hundred thousand leaked passwords from eleven websites, researchers estimated that 43 to 51% of people use the same password on more than one site. Many of the rest change it only slightly from site to site, in ways an attacker can learn. A password chosen once, for one account, quietly ends up guarding many others.