Online Concerts: Pick of the clicks There are superb concerts amid bloopers and home videos on YouTube. But musicians are unhappy about having their mistakes broadcast - for free. By Jessica Duchen

My first alert to the musical potential of YouTube.com came from the stat-counter on my classical music blog. A reader had found my site through a Google search for a friend of mine, a well-known pianist, followed by the word "nightmare". Puzzled, I investigated. Someone had posted on YouTube a video of him suffering a memory lapse in a concert. The offending sample, fortunately, was rapidly removed.

Then another incident struck. The cellist Amanda Forsyth, (oppposite right) aka Mrs Pinchas Zukerman, dislocated in the middle of a concerto, had allegedly let rip at the conductor in a tirade worthy of John McEnroe. The event had been captured and posted on YouTube. Again, it vanished before I could see it, but the number of hits on my blog from searches on "Amanda Forsyth YouTube" still rocketed. This unfortunate musician is now world famous, but for all the wrong reasons.

In case I'm not the last person on earth to discover the concept that is YouTube, here's what happens: anyone can sign up for free, hide their identity with a user name and then upload short videos they've made. Viewers can perform specific searches or browse through categories. Comments and ratings are invited. You can track the contributions of interesting usernames (I followed "wmozart" and "oistrakhmilstein" for starters) and share your favourite videos.

It's a jungle out there, even if you're looking for something as ostensibly innocuous as classical music. You have to surf through some unbelievable dross - innumerable people have uploaded videos of themselves playing Für Elise or Clair de lune, perhaps hoping the director of Carnegie Hall will stumble across the extract and recognise them as the next Horowitz. There's also an eye-opener over the fond, false hopes of over-ambitious parents. One mum has captured her kid scratching out two open strings on his/her new violin and headed it "Child prodigy?" Elsewhere, the same heading heralds a Japanese eight-year-old performing a not-very-difficult Kreisler piece not very well, her eyes nearly lifeless behind her little round spectacles.

Still, once you're past the voyeurism of the Amanda Forsyth incident and the horrors of the home movies, it's possible to unearth performances of astonishing historical value. In one sitting, I found a ton of films of legendary dead pianists like Vladimir Horowitz, Emil Gilels, Sviatoslav Richter and Glenn Gould, as well as living ones including Martha Argerich, Evgeny Kissin, Grigory Sokolov and Krystian Zimerman. Among historical violinists I found dazzling footage of Jascha Heifetz and Henryk Szeryng and, from 1929, a tantalising silent video of Bronislaw Huberman, who is said to have drawn tears from Brahms himself. And who knows what more will have been posted by the next time you log on?

Being a ballet nut, I whiled away a morning glued to the gravity-defying leaps of Rudolf Nureyev, the limpid, exquisite dancing of Galina Ulanova, and extracts from the debut in 1947 of the Bolshoi prima ballerina assoluta Maya Plisetskaya in Swan Lake. Opera buffs, too, can enter an Aladdin's cave: among gems I discovered were clips of Fritz Wunderlich, who died in 1966 aged barely 35, duetting with Hermann Prey in Il barbiere di Siviglia, and also performing the most heartrending account I've ever heard of "Lensky's Aria" from Eugene Onegin. As for contemporary singers, videos of Juan Diego Florez (opposite left) kept me smiling for hours. Viewer commentaries range from the imbecilic and obscene to some intelligent discussions about different fachs and how falsetto is achieved.

Then a violinist friend in the US e-mailed me a YouTube link to a French film from 1935, part of a series called Cinéphonie. The greatest of French 20th-century violinists, Jacques Thibaud, is heard and briefly seen playing Szymanowski's glittering, sensual piece La fontaine d'Aréthuse, while the myth of Arethusa is enacted amid a forest by an actor in a tunic and a curvaceous actress in nothing whatsoever. I'd never have found this on DVD in Woolworths. It's priceless.

And that's the conundrum: price. There isn't one. Anyone can watch YouTube for free, and anyone can upload to it any digital video they like. These are often filched from existing professional films, most of which are presumably still in copyright. Also, people have clearly smuggled into concerts digital cameras, snaffled samples of the show and put them on YouTube. As far as I can tell, copyright, union regulations, recording fees, royalties and so on are utterly bypassed. Anyone seen pirating a performance should be thrown out of the hall on the spot - that's what ushers are supposedly for.

The artists are not happy. One soprano I interviewed told me that she'd been horrified to discover on YouTube an illegal video of her performing, badly filmed and with terrible sound. It should be done properly, she pointed out, by professional film or TV companies. The problem is that, generally, it isn't. Filming opera is such a horrendously expensive business that public service broadcasters don't do it enough. Concerts, with the exception of the BBC Proms, have vanished from publicly funded TV in the UK. Record companies are falling to pieces. The numbers in which music, opera and ballet videos are viewed on YouTube - around 150,000 for Juan Diego Florez - wouldn't have displeased record labels until just a few years ago, but probably do now, and are of no interest to broadcasters chasing Big Brother ratings.

The demand is there; it's the professional supply that's drying up. With the broadcast and recorded arts in the direst straits possible, no wonder punters are taking matters into their own hands. Without YouTube, music-lovers would never see those rare historic delights - or inspiring contemporary performances.

I don't approve of the flouting of copyrightand the rest of it. Still, if the two options are being able to watch Fritz Wunderlich or not being able to watch Fritz Wunderlich, I'll plump for the former every time. And YouTube brings him direct to my computer with a couple of clicks, scot-free.