The British Phonographic Industry (BPI) is to sue individual music fans who swap song files over the internet.
The BPI says downloaders spend less on albums and singles
This follows action by the Recording Industry Association of America (RIAA), which has sued more than 3,000 downloaders.
BBC News Online looks at what this could mean for music swappers around the world, and the issues behind the latest tactics.
I have downloaded music over the internet. Can I be sued?
Not if you have downloaded songs that have been put online with the approval of record labels and artists - which usually involves paying for royalties. Sanctioned services include Apple's iTunes and Napster as well as MyCokeMusic, Wippit HMV and Virgin.
The industry is targeting uploaders - those who make available tracks in their collection for other people to download - whether it is one song or a million. If you are an uploader, you are infringing copyright and run the risk of being sued.
Could I be sued for swapping just a few songs?
Theoretically, you could. But the BPI says the problem stems from a small hardcore of "serial uploaders" who offer hundreds or thousands of music files over the internet.
The RIAA took action against a college student in Michigan who ran a network offering more than 650,000 files - the equivalent of more than 43,000 albums. They have chased other users who have again uploaded thousands of files.
The BPI says 15% of file-sharers are responsible for 75% of all songs swapped illegally.
Can children be sued for uploading?
The BPI said it cannot differentiate between children and adults in its legal actions because it does not actually know their identities. Personal information is handed over by internet service providers once the BPI decides who it wants sue.
But if it is a minor uploading music, then the BPI says it could still pursue legal action.
Why are record companies so worried?
Music sales are falling, with global annual record sales down from $40bn (£22bn) to $30bn (£17bn) over the past four years.
The music industry, which has suffered massive redundancies and restructuring in the last decade, says the swapping of music files over the internet is one of the major parts of music piracy. It has sued online song-swapping services like Napster, and is in the process of suing Kazaa.
However, CD sales in the UK are rising - up fractionally on last year.
Why is the BPI taking action now?
In 2003 the BPI said suing individual users would be a "last resort".
But recent research indicates that eight million people in the UK claim to be downloading music, 92% of them using illegal sites.
Why are they chasing individual users?
The music industry has had mixed fortunes in its court actions against the companies that support file-swapping on the internet. Some have been successful - like the action which forced Napster to close - and some have not.
In 2003 a US judge ruled that two file-swapping networks, Grokster and Morpheus, were not responsible for what was traded on their systems.
But in 2005 this was overturned by the US Supreme Court, which ruled file-sharing networks such as Grokster could be held responsible if they intended for their customers to use software primarily to swap songs and movies illegally. This means the legal attention could yet shift back to the networks.
The RIAA has also been successful in getting telecommunications giant Verizon to hand over details of customers who swap files. This has allowed them to begin the process of gathering evidence against individuals.
Are other music industry groups going to take similar action?
Germany, Switzerland, Denmark, Spain and Italy have already taken similar action, says the International Federation for the Phonographic Industry (IFPI). German police impounded computer equipment in 2003 in the town of Furth that had been used to upload up to one million files. In Italy at least 75 actions have been taken.
Will legitimate online services ever rival the peer-to-peer sites?
More than three million downloads have been sold in the UK so far this year - but that figure remains a small fraction of the total number of songs traded online illegally.