Raphael Gray, a 19-year-old from Clynderwen in West Wales, called himself the "saint of e-commerce" and said he was on a mission to highlight security dangers on the Internet. The only problem was that to do this, he cracked thousands of computer networks and gained access to more than 23,000 credit card numbers.
He posted thousands of the numbers on the Web, leading to roughly $4 million (2.8 million pounds) in fraudulent credit card charges and causing two companies to close.
His best-known stunt, however, was using Bill Gates' own credit card number to mail-order the Microsoft chairman a large shipment of Viagra.
Gray's mission brought him to the attention of the FBI, which was "greatly troubled by his disturbed crusade," according to prosecuting lawyer Leighton Davies. Gray admitted to stealing credit card information from sites including Feelgoodfalls.com, Mostorefront.com, Albionsmo.com and the American Society of Clinical Pathologists' Web site.
The teenager had previously pleaded not guilty to charges of breaking section 10 of the Computer Misuse Act--legislation designed to combat computer crime--by downloading unauthorized material.
Colin Nicholls, defending, said that Gray suffered from a medical condition that made community rehabilitation necessary. "He was obsessed by his crusade--he is a highly strung man going through an abnormal period in his life," Nicholls said.
Staff writer Matthew Broersma reported from London. Staff writer Will Knight contributed to this report.