British and Dutch police have shut down a "widely-used" source of illegally-downloaded music.
Police also raided the home of the IT worker's father
A flat on Teesside and several properties in Amsterdam were raided as part of an Interpol investigation into the members-only website OiNK.
The UK-run site has leaked 60 major pre-release albums this year alone, said the International Federation of the Phonographic Industry (IFPI).
A 24-year-old man from Middlesbrough was arrested on Tuesday morning.
The IT worker was led from his home in the town's Grange Road and is being questioned on suspicion of conspiracy to defraud and infringement of copyright law.
At the same time his employer - a large multi-national company - and his father's home were also raided.
A Cleveland Police spokesman said: "This extremely lucrative and creative scheme consisted of a private file-sharing website being set up. Membership was by invitation only.
"The site allowed the uploading and downloading of pre-release music and media to thousands of members."
An IFPI spokesman said: "Once an album had been posted on the OiNK website, the users that download that music then passed the content to other websites, forums and blogs, where multiple copies were made.
"Within a few hours of a popular pre-release track being posted on the OiNK site, hundreds of copies can be found further down the illegal online supply chain."
The site's servers, based in Amsterdam, were seized in a series of raids last week.
It followed a two-year investigation by music industry bodies the IFPI and the British Phonographic Industry (BPI).