LinkedIn suffered a data breach of nearly 6.5 million users in 2012. A hacker going by the name Peace was discovered trying to sell 117 million LinkedIn credentials for the price of 5 bitcoin, equivalent to US$2250. LinkedIn has urged its users to enable two-factor authentication for their accounts but it is unlikely, considering the blatantly obvious disregard for even basic password security such as choosing complex passwords, the message will be taken seriously. If proven authentic, it is likely that users will see an increase in other attacks where email and passwords can be used to gain access to accounts other than LinkedIn.”]
Source: http://securityaffairs.co/wordpress/47691/data-breach/linkedin-breach-2012.html