To most music fans the plaintive Swedish strummers Peter Bjorn and John must seem an inoffensive bunch. So the Stockholm trio were are surprised as anyone to find an army of protesters boycotting their performance in a Texas record store.

Navigating the objector who scrawled “PBJ” on duct tape covering his mouth, it dawned on the group that they had become the victim of instant blogging, the phenomenon that defined this year’s South by Southwest (SXSW) festival in Austin.

With 2,000 artists to assess over four days at the annual talent-finding binge, the self-appointed music gurus of the internet hold the fate of aspiring bands in their laptops. Delegates observe performers with a free beer in one hand and a digital camera in the other, ready to upload images on the net, which are then subject to instant judgment by bitchy blogging rivals. Others slouch at the back of halls, sending contemporaneous reviews via wireless connections before the band has even left the stage.

This is how Peter Bjorn and John came to grief. The Wrong Folks blogger despaired that the group were being hailed as an SXSW “buzz” band at a showcase hosted by the influential US music site Pitchfork. “ Young Folks was catchy and harmless, but this band is not a significant band. Peter Bjorn and John must be stopped,” concluded the blog.

Within hours the band-wagon was rolling. An emergency blog, Stop Peter Bjorn and John, appeared and “haters” signed up to protest in person at the overexposed band’s SXSW performances.

Yet MP3 blogs are just as often a vehicle for the positive passions of their authors. With cash-strapped major labels cutting back their SXSW expenditure, leading blogs such as Stereogum hosted their own concerts, choosing the pick of hot acts.

Front-row footage of the Stereogum-staged reunion of the Kurt Cobain favourites the Meat Puppets was posted on YouTube within minutes of their performance, and it was received with positive comments.

The Glasgow indie band Popup, seeking to create their own buzz at the event, have seized on the digital opportunities. “We booked an entire US tour, from finding promoters, venues and floors to sleep on through our MySpace page,” says their manager, Alec Downie. An 18-year-old fan put the quartet up in Houston while his parents were away.

They do not want to give all their songs away free on MP3 blogs – “We have to make a living,” says Downie – but they are delighted when fans ask if they can link songs that they have heard live to their MySpace profile pages.

Working the online space is as important as whipping up a live crowd, agree their fellow Glaswegian rockers on the SXSW trail, the Hedrons. “It’s strange that people we’ve never met are blogging about us straight after gigs,” says the drummer, Soup. “We’ve all got our laptops and are very proactive on MySpace.”

You don’t have to take the NME’s word that the tattooed Brit-punk shouters Gallows were the hit of SXSW: their ear-splitting club show is available from multiple angles on YouTube.

But with Viacom filing a $1 billion copyright infringement suit against YouTube and its parent company, Google, the golden age of free image sharing may be coming to an end.

But, as Hilary Clinton learnt this week, opinions cannot be silenced. Fresh from their victory over the fey Swedish popsters, the Wrong Folks are seeking new targets in their battle of the blog. “If there’s one thing that blogs have taught us it’s that those of us who try hard enough really can affect the culture,” claim the Folks.

“We make these bands ourselves, online, though our posts, listens, downloads and links. If we want to take them down, we can. In the case of Peter Bjorn and John, we must. As for how, I will get into that in the next post.”

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