AS A consequence of the ascendancy of guitar rock in the charts, sales of acoustic and electric guitars are bigger than ever.

Last year, more than €140 million was spent on guitars in Ireland and Britain. All very good for music at a grassroots level, but it's also thrown up a weird legal anomaly that once again shows up the legal wing of the music industry as being one of the most petty-minded and wilfully obstructive concerns going.

This all goes back to the old music piracy argument. An argument used by the illegal downloaders in the early days was that because there simply wasn't a legal alternative, they had no choice but to get music where they could. With iTunes and all the other options available now, this argument is redundant. But it's still very much alive when it comes to guitar "tab" sites. Simply put, a guitar tab is a form of musical notation that tells players where to place their fingers on the fretboard. Guitar tablature is vital for beginners or those who simply want to play along to Stairway to Heaven or Smoke on the Water or whatever guff takes their fancy.

You can buy guitar tab books, although they are increasingly hard to find and many people just go straight to sites such as www.olga.net, which has 34,000 tablatures in its archive. However go to olga.net today and you will be greeted with the following message: "Olga is currently offline while we attempt to resolve legal issues with the archive. We received a 'take down' letter from lawyers representing the NMPA and the MPA [both US music publishing organisations]. We greatly appreciate your support and hope to return to providing resources to the aspiring guitarist as soon as possible."

The case of the music publishers and their "cease and desist" order is quite clear: the guitar tablature for any song is copyrighted. The President of the NMPA, David Israelite, says that the unauthorised use of tablature "deprives the songwriter of the ability to make a living, and is no different than stealing".

However, and here is where it gets complicated, the free online guitar tab sites argue that they are not doing the equivalent of buying the official guitar tab book, copying it and putting it up for free on the net. They say their sites only represent the "interpretation" of a song - in that, people with a good deal of musical knowledge are able to "decipher" for themselves how the guitar tab goes.

One very peeved free guitar tab site user has posted an observation about this new legal stricture which seems to crystallise the whole argument. The poster writes: "As a guitar player since the age of 12, I have frequently used internet guitar tab sites as an aid to learning. The officially endorsed guitar books are grossly overpriced and are very limited in their coverage of music. For many it's a challenging hobby transcribing the latest songs. To me this is on a totally different level compared to swapping MP3 files. Would I be faced with a lawsuit by writing down the chords to a new song on a scrap of paper and handing it to a friend? This idiocy must stop. What next? Suing people for singing lyrics in the street?"

There is not a huge amount of money involved here and, in an echo of the whole Napster/ Metallica debacle, those opposed to these new legal actions argue that free access to hugely successful songs is not going to damage the artist who holds the copyright and is usually only used by people who have already bought the official album and now want to play along to the songs.

You might think that the simple alternative is the equivalent of iTunes (as in legal and regulated) in the online guitar tab world. But would anyone actually pay for something when they can work it out for themselves? And by the way, that bit above about suing people for singing lyrics in the street: It's legally permissible and has happened (after a fashion) in the music world before. But we'll get back to that some other time.