Sony

( Danish Siddiqui / Reuters )

What happened: Sony shut down the PlayStation Network and Qriocity music service on April 20 and waited a week to announce that its Web-based services had been hacked and that personal information, including 10 million credit card accounts, could have been accessed.

The apology: "I know this has been a frustrating time for all of you," Sir Howard Stringer, Sony president and chief executive, wrote in a May 5 letter. "Let me assure you that the resources of this company have been focused on investigating the entire nature and impact of the cyber-attack we've all experienced and on fixing it... As a company we — and I — apologize for the inconvenience and concern caused by this attack."