Yancey Strickler, CEO of Kickstarter writes:
On Wednesday night, law enforcement officials contacted Kickstarter and alerted us that hackers had sought and gained unauthorized access to some of our customers’ data. Upon learning this, we immediately closed the security breach and began strengthening security measures throughout the Kickstarter system.
No credit card data of any kind was accessed by hackers. There is no evidence of unauthorized activity of any kind on all but two Kickstarter user accounts.
While no credit card data was accessed, some information about our customers was. Accessed information included usernames, email addresses, mailing addresses, phone numbers, and encrypted passwords. Actual passwords were not revealed, however it is possible for a malicious person with enough computing power to guess and crack an encrypted password, particularly a weak or obvious one.
Read more on Kickstarter.
N.B. In response to a question on Twitter about the encryption referred to, Kickstarter answered: “Old passwords used salted SHA1, digested multiple times. More recent passwords use bcrypt.”