Well, delegates at the Chicago-based event in March decided they'd better get the bad news over fast. They flocked in to the opulently chandeliered meeting room to hear Robert Kozinets, assistant professor of marketing at Kellogg School of Management, Northwest University, describe what they were up against.

Each year the Nevada desert plays host to a huge temporary community, each paying $250 for the privilege, who share a week of food, drink and striving in a barren environment.

They focus on shared rituals, seeing it as an opportunity for radical self-expression and self-reliance. At its inception, it was an anarchists event, 'skeet shooting with propane', attracting some 60 people in 1990. Last year some 30,000 took part.

This community, called Burning Man after the looming effigy that is burnt there, is just one of many bound by their love of entertainment such as X Files and Star Trek fans and united against consumption such as the virtual boycotters behind the growing Buy Nothing Day movement.

Kozinets, an anthropologist by training, described how he was allowed to attend and observe ­ but only as long as he participated. After all, he said, ethnography means never having to miss the party. Then you have to write it up.

He told of the calibre of attendees, who ranged from technofreaks and ad agency executives, to people on the client side, too. The event, which started in 1985 in San Francisco, is held annually.

His video showed one young marketer who admitted: "Yes, I'm in marketing" and then, slightly shamefacedly: "and I like it, too!" Yet all of those attending sign up to a festival where no brand names can be sold ­ or bought. The only exchange of any kind is through barter (although for addicts cappuccinos, lattes and ice are available).

He explained how big brand names are keen to exploit communities of this type ­ and somehow a vision was conjured up of McDonald's and MTV lorries circling the community's wagons in the desert, just waiting for an opening.

That's not to say that brand names never appear. A freezer truck containing frozen ice creams was driven into the desert, and they were given away as a gift. "But this wasn't sampling," says Kozinets, "they were given by a benefactor. 'Decommodifying Dove' as it were".

So what are the implications? Well, it doesn't mean that the death of the big brand is nigh, but that we could be watching the 21st Century equivalent of the spiritual retreat, a hyper community recreating a caring, sharing environment but also mirroring the impermanence that many experience in their normal lives.

This is also a community making a stand, stating that there are two kinds of consumption: the passive, mindless kind, influenced by others, and the ritual, sacred, meaningful kind, experienced in a festival context.

There are only two slogans to be heard at Burning Man: "Piss clear" and "Leave no trace", signifying attendees' desire to leave the environment intact. Maybe Glastonbury should take note.