Seen on haveibeenpwned.com: 1,476,783 accounts dumped:
In February 2016, the Russian portal and email service KM.RU was the target of an attack which was consequently detailed on Reddit. Allegedly protesting “the foreign policy of Russia in regards to Ukraine”, KM.RU was one of several Russian sites in the breach and impacted almost 1.5M accounts including sensitive personal information.
Compromised data: Dates of birth, Email addresses, Genders, Geographic location, Recovery email addresses, Security questions and answers, Usernames
Update: Motherboard has more on this hack and the hack of Nival.com, also by the same hacker, “Cyber Anakin.”