An online gift certificate company said a hacker that blackmailed it for weeks after pilfering its customer information has apparently carried out threats of disclosing the data to its customers. Webcertificate.com customers reported getting an email message that included their home and email addresses. "I hate to inform you that your account has been hacked," said the email, viewed by this reporter, from someone identified as Zilterio. Webcertificate, a unit of electronic-payment company Ecount, was hacked on 21 August, a representative said. Shortly afterward, the hacker, who also claimed to have stolen credit card numbers of 350,000 of the company's customers, contacted Philadelphia-based Ecount and tried to extort the company, said Matt Gillin, Ecount's chief executive. The caller demanded $45,000 (£31,500) in exchange for not disclosing the information. The company refused to meet the demands, Gillin said. After notifying the FBI, Ecount informed customers on 28 August that the break-in had occurred, and it assured them that their credit card information was safe. Because the company stores credit card information offline, it would be impossible for the hacker to steal it electronically. What the hacker thought were credit card numbers were really 16-digit serial numbers used to identify gift certificates. Ecount has cancelled those codes. "There is no financial liability to the company or our customers," Gillin said. The FBI could not be reached for comment. Hackers continue to plague the Internet even as technology companies have poured millions of dollars into developing security technology. But the costs of fortifying a Web site with the latest security technology can be enormous, and often hackers prove to be more than a match for the electronic barricades. Companies such as Amazon.com-owned book service Bibliofind.com, Creditcards.com and Egghead.com, which recently filed for bankruptcy protection, have seen their sites broken into and customer information--in some cases, credit card information--swiped by thieves. Executives of Ecount said they anticipated the hacker would email customers whose information was stolen. Last week, the company tried to pre-empt the hacker when it warned customers to expect a message from the hacker and informed them why the company would not agree to the hacker's demands. In the email to Webcertificate customers from Zilterio, the author declares that the security breach was a result of "weak security", an apparent attempt to embarrass the company. Ecount said the attempt to undermine the company's relationship with its customers failed; most customers support the company in its fighting against Internet thieves. But some damage may have been done. One customer told this reporter that she would no longer use Webcertificate. "This disturbs me, that this guy has all of my personal information," said Nancy Parker, a frequent Webcertificate customer over the past two years who was shocked to see her personal information in the email. "What's from keeping it from happening again?" Gillin said that immediately after the attacks, the company began bolstering the site's security. "We're doing all we can to make sure that this never happens again," he said. See the Viruses and Hacking News Section for the latest headlines. See the Net Crime News Section for the latest on hacking, fraud, viruses and related issues. See the Internet News Section for full coverage. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Security forum. Let the editors know what you think in the Mailroom. And read other letters.