We all make mistakes, but when you're a public figure like Mark Zuckerberg, a small mistake can turn into something huge.The Facebook founder's Twitter and Pinterest accounts were hacked by the anonymous group, OurMine, this weekend, reports NBC News. The hackers alerted Zuckerberg to the breach when they tweeted at him yesterday — their Twitter account has since been suspended . The group said they hacked Zuckerberg's Instagram account, as well, but Facebook reports that's not true . Zuckerberg's Facebook account was also not hacked.Anyone in the public eye is vulnerable to an online attack, but OurMine exposed Zuckerberg's fatal flaw — he used the same password for multiple accounts, a password likely leaked in the 2012 LinkedIn hack that saw 117 million account details sold on the dark web.The password Zuck used? "dadada."Since alternating passwords is one of the cardinal rules of password creation, it is humiliating that the tech genius didn't follow the security standard. And while Zuckerberg didn't make the mistake of using his birthday or the number sequence, 1234, "dadada" is certainly not a bastion of security strength.Considering Zuckerberg hasn't tweeted since 2012 (and even then, only sparingly), it's likely he completely forgot about the account and its ill-conceived password, and the fact that he'd reused it. Luckily, Zuckerberg must employ a more robust password on his Facebook account.You can follow these rules to make sure you don't make the same error as Zuckerberg, and check out the Today show's coverage of the breach, below.