Hackers obtained the customer information of nearly 3 million Adobe custoemrs who used Photoshop, InDesign, Premiere, and other Adobe software products. Customer IDs, encrypted passwords, names, encrypted credit or debit card numbers, expiration dates, and other information related to customer orders were exposed. Anyone who bought software directly from Adobe's website is advised to change their Adobe account passwords.
UPDATE (10/11/2013): Hackers kept the source code on a hidden, but unencrypted server.
UPDATE (10/21/2013): A second breach related to the initial one in early October caused Adobe to reset client passwords.
UPDATE (10/29/2013): An investigation revealed that the encrypted passwords of approximately 38 million active users were also exposed. Adobe IDs were also compromised and were reset by Adobe after the breach.
UPDATE (11/20/2013): Around 42 million passwords for the Australian-based online dating service Cupid Media were also found on the same server that contained stolen Adobe, PR Newswire, and National White Collar Crime Center information.
UPDATE (11/25/2013): Some estimate that 152 million Adobe ID accounts were in a file that began circulating the internet in late October. Adobe systems Inc has encountered delays in trying to notify all customers of the issue since it was discovered 10 weeks ago.