The recent, near-orgasmic buzz on the blogosphere and social networking sites suggested nothing less than the Second Coming; a musical visitation of such potency and power that the recession would end and the electoral crisis in Iran would be solved at a stroke. Forget your troubles and woes because a band are going to play a selection of songs released quite a while ago to people who weren't around when the band and records in question were.

So, another week, another reunion then.

Just as Blur complete their reformation stint, the jury is arguably still out as to whether it's all been worthwhile. Their legacy, of course, is a strong one. A cultural response to the perceived dominance of American music, Blur ensured that their Britishness was indelibly stamped across their output. Though debut album Leisure was little more than a retread of baggy glories already gone by, their experiences in America lead to the regeneration that was Modern Life Is Rubbish. Along with Suede - a band that has criminally fallen under the cultural radar - Blur were responsible for kick-starting a sense of pride that, in the initial stages at least, didn't need to look beyond these shores to make great music.

As ideology began to fade and the last remnants of John Major's administration began to offer some kind of economic stability, dramatic changes at Radio 1 soon saw the station widening its playlist to the effect that the music you'd have to wait until after the sun had gone down to hear was now available to all. And while Parklife caught the zeitgeist of '94 and its follow-up, The Great Escape, mugged shamelessly to the gallery, Blur and _13_ were the sound of a band finding their feet again.

There are of course mutterings from the Blur camp that new material may yet indeed materialise and, given the high quality musical output of Coxon and Albarn since the pair's split, the possibility of something to actually look forward to remains high.

But what of the Pixies, a band that helped shape the musical map and steered the course of musical history an' all? Other than a tasteful repackaging of existing material, you ain't getting anything new: you're watching a once-important band becoming their own tribute act and that, whichever way you slice it, can't be right.

See, back in the mists of the 1980s when Thatcherism changed the industrial face of Britain thanks to a policy of unfettered greed and deregulation and the airwaves were ruled by a conspiracy of self-serving, cardigan-wearing, pipe-smoking dullards and the monstrous evil that was Stock Aitkin & Waterman, Pixies' Come On Pilgrim and Surfer Rosa were like dispatches from another planet. A complete breath of fresh air, this was music that kicked against the pricks of mainstream mediocrity; music that, through a combination of rudimentary musicianship, the power of hardcore punk, sun-kissed Californian melodies, surrealist lyrics and a dynamic so up against the prevailing, force-fed trends that it couldn't fail to excite a generation that refused to believe that the answer lay with anorak-wearing shamblers or production-line chart fodder. This was music that picked up the long ball driven by the hardcore fury of Husker Du before driving into the six-yard box occupied by Cobain and...GOAL! Put into the context of time and culture, the albums released by Pixies between 1987 and 1991 stood for something as they forged ahead and drew battles lines in the sand. Nostalgia it wasn't.

And now, 18 years since the release of Trompe Le Monde and five since their initial reunion, we've still to hear a note of original music from the Pixies. In that time, Kim Deal has released Mountain Battle with The Breeders, Frank Black has let loose almost an album per year, Joey Santiago snuck out an album with The Martinis and Dave Lovering has probably learnt a few new magic tricks. But then again, listening to those largely forgettable releases, a new Pixies album would do much to shit all over a near-faultless legacy.

Indeed, speaking this week with Spinner, Frank Black said: "I guess we're kind of like a Led Zeppelin that tours. More accurately, we would be like a Velvet Underground that tours. We have a catalogue and it has a certain cache, and it seems to always be kind of current over and over to current musical tastes. Some of it, anyway, has a certain timeless quality to it."

So there you have it: Pixies have headed off the Australian Pixies at the pass to become a unit that celebrates itself and former glories. Big whoop.

We're still waiting for the dust to settle on the current reunion of The Specials. Rooted to a particular cultural resonance and, given the current economic shitstorm, The Specials sound as depressingly relevant as they did thirty years ago. Just listen to 'Do Nothing' or 'Ghost Town' or 'Too Much Too Young' or... well, you get the picture. But what would be utterly deflating would be for the band to carry on beyond their touring activities this year without addressing the here and now and becoming a hipper version of Bad Manners.

The crucial thing with back catalogues and reunions is context. Listening to the stuff released by Pixies, Blur, The Specials et al back in the day was to view a snapshot of a particular time and place by offering social commentary or reacting against conventional wisdom. Now, co-opted as yet another facet of the entertainment industry, the danger of neutering and sterilisation remains very real.

The misguided fools clamouring for a Stone Roses reunion would do well to check the historical evidence: the Roses were crap live. Spike Island? Divorced from the reality of the situation - an noxious chemical dump in the middle of an industrial estate with poor facilities, a polluted atmosphere and Ian Brown's goddawful honking - the myth takes over. The supposedly legendary Alexandra Palace gig? A piss-weak anticlimax made slightly bearable by being on one. Sorted. The only acceptable Stone Roses reunion would be a Don't Look Back Session where they'd be forced, at gun-point, to play The Second Coming in its entirety - and that's including those shitty hidden tracks - and nothing else.

But that's not to dismiss reunions outright - they can and indeed do, on occasion, work. Following the Herculean levels on internecine squabbling and psychological warfare that tore them asunder, who'd have thought that Dinosaur Jr would have ever got back together? More importantly, who'd have actually have bet money on these near-somnambulistic arch slackers releasing not one, but two post-comeback albums? Or that they stand up pretty well to the releases that forged their reputations? Strange days indeed...

Similarly, The Go-Betweens. Once a band with a selective audience (that'll be students and music journalists), The Go-Betweens returned after a 12 year hiatus to release with The Friends Of Rachel Worth, Bright Yellow Bright Orange and the stunningly gorgeous Oceans Apart, and in the process made some of the best music of their career.

The most remarkable comeback of recent years was that of Krautrock supergroup Harmonia. Their appearance at the South Bank's Queen Elizabeth Hall in April 2008 made the grade for a number of reasons. Firstly, they'd never played outside of Germany. Secondly, no one knew what expect. Thirdly, rather than aping their two studio albums, Musik Von Harmonia and Deluxe, the ageing trio played a set of entirely new and genuinely convincing material that only made the slightest of concessions with a thoroughly revamped reading of 'Deluxe (Immer Weider)' during the encore.

So unless your reunion of choice is offering anything new, don't kid yourself that you're seeing the same thing that appeared first time round. You're not. More likely you're seeing light entertainment, a money making extension of the X Factor/BGT tour that, devoid of context and no new material, means nothing other than a trip down someone's memory lane. And why do that when you could be creating your own magic? After all, music's not that shit these days, is it? Well, is it?