The company, under fire since hackers accessed personal data from about 100 million user accounts of its PlayStation Network and PC-based online gaming services, said in a statement details posted on the inactive website also included three unconfirmed e-mail addresses.
The data came from customers who entered a 2001 product sweepstakes contest. The list did not include information on credit cards, social security numbers or passwords.
"The website was out of date and inactive when discovered as part of the continued attacks on Sony," Sony said, adding that the company took the website down shortly after finding out about the postings on Thursday.
Sony Chief Executive Officer Howard Stringer apologised on Friday to users of the firm's PlayStation Network and other online services, breaking his silence on the massive data breach.
The company said last Sunday that it would begin restoring services within the week but a spokeswoman said on Saturday this would not be possible, and that no date had been fixed for when services would resume.
The incident may prove to be a significant setback for a company looking to recover after being outmanoeuvred by Apple (AAPL.O) in portable music and Samsung Electronics (005930.KS) in flat-screen TVs.
In video games, it faces a tough fight with Nintendo's (7974.OS) Wii game console and Microsoft's (MSFT.O) Xbox.
"This wait is becoming so tedious. I know there needs to be a lot of testing, but it is really getting annoying. I am seriously considering changing to the Xbox," said message posted by a user called Cryonic UCX on the U.S. PlayStation blog.
"I LOVE my PlayStation, but Sony is not doing well in the online. Sony, you need to step your game up!"
On Friday, Sony shares ended 2.3 percent lower in a broader .N225 market down 1.5 percent, extending its total losses to about 6 percent since it revealed the breach. The Nikkei is up around 3 percent over the same period.
Sony issued its first warning on the PlayStation break-in a week after it detected a problem with the network on April 19, infuriating many users around the world. Sony said it needed time to work out the extent of the damage.
The hackers have not been identified, but Internet vigilante group Anonymous, which had claimed responsibility for previous attacks on Sony and other corporations, denied it was behind the data theft.
The group's statement came after Sony said Anonymous was indirectly responsible for the attack on the company.
Sony, which is set to report its annual earnings on May 26, has yet to specify the financial effect of the network breach.
