Hackers gained unauthorised access to Kickstarter last week stealing the personal information of a number of users.
Information accessed by hackers included usernames, email addresses, mailing addresses, phone numbers and encrypted passwords.
Kickstarter CEO Yancey Strickler said while no full passwords would have been taken, it recommended users change them in case they are cracked.
No credit card data is said to have been accessed. Strickler said that there was also no evidence of unauthorised activity of any kind on all but two user accounts.
In a message to users, Strickler apologised for losing personal information and promised to improve its security procedures.
"We’re incredibly sorry that this happened," he said.
"We set a very high bar for how we serve our community, and this incident is frustrating and upsetting. We have since improved our security procedures and systems in numerous ways, and we will continue to do so in the weeks and months to come. We are working closely with law enforcement, and we are doing everything in our power to prevent this from happening again."