Sony said Saturday about 2,500 customers' names and partial addresses stolen by hackers had been discovered posted online as it struggled to recover from the biggest-ever Internet security break-in.
"The website was out-of-date and inactive when discovered as part of the continued attacks on Sony," US-based Sony Electronics said in an online statement.
The data belonged customers, mostly Americans, who had entered a 2001 product sweepstake, the company said.
The company "immediately took the website down, and we are aggressively removing any residual links to the list", it said, without giving further details on the site.
Sony said it would offer US PlayStation Network and Qriocity users free membership for 12 months in a deal that would include a $1 million per user insurance policy against identity theft.
Sony in Japan also said Saturday that it is unlikely to meet its self-imposed deadline to restore the PlayStation Network and other online services.
But it said Saturday: "The company is taking time to strengthen the protection and coding of data, in addition to building necessary surveillance functions for actualising higher security.
"The company will resume the services in stages in different regions after assuring the safety of customers," it added in a statement.