If you have a Kickstarter account, you're going to want to change the password, as the site is the latest to be infiltrated by dastardly hackers, showing that hacking is not as cool as it appears in games sometimes. Kickstarter say that while some user data was accessed - including, worryingly, "usernames, email addresses, mailing addresses, phone numbers, and encrypted passwords" - no credit card information was able to be retrieved. While actual passwords weren't revealed, they're advising users to change them anyway, ideally to something more secure. 'Password1', by the way, is not secure.
If you're worried that your accounts may have been in any way messed around with, know that only two people have had their accounts engage in any "unauthorised activity", and that they've already been contacted by Kickstarter. The good news here is that Kickstarter doesn't store full credit card numbers, and that these weren't accessed anyway. If you have any other questions or worries, this page should help.
(Thanks, Kotaku .)