How many victims? Unknown.
What type of personal information? Names, Social Security numbers and compensation information.
What happened? The thief used the data to "annoy" individuals but did not send the information to any third parties, according to an internal email sent to affected employees. In addition, no bank account or medical information was compromised.
What was the response? All MySpace employees were notified about the incident by email.
Source: http://www.switched.com/, Switched, “MySpace Fires Employee After Data Breach,” April 18, 2009.