In September, Yahoo shocked the world when it revealed that at least 500 million user accounts had been breached. At the time, the breach was believed to be the largest theft of personal data from a major technology company ever. Making matters even worse, Yahoo later disclosed that the hack itself had happened in 2014 but only came to light in 2016, so the attackers had access to user information for years.

But it turns out that was just the warm-up. In mid-December, Yahoo dropped the jaw-dropping revelation that a separate hack occurred around August 2013 that leaked the data of one billion users—double the record-breaking hack from September. This is why strong, unique passwords for every site and service you use is important, people.