gzipped_tar writes "The 'Chinese Software Developer Network' (CSDN), operated by Bailian Midami Digital Technology Co., Ltd., is one of the largest networks of software developers in China. A text file with 6 million CSDN user credentials including user names, password, emails, all in clear text, got leaked to the Internet. The CSDN has issued a letter of apology to its users. In the letter, it is explained that passwords created before April 2009 had been stored in plain text, while later passwords were encrypted. Users created between September 2010 and January 2011 may still suffer from email address leaks. A summary of the most frequent passwords without the corresponding usernames is available at GitHub. Somewhat surprisingly, the cryptic sounding password 'dearbook' ranks 4th with 46053 accounts using it."