In an age of free downloads and streaming services, playlists are now chosen by myriad tastemakers and endlessly disseminated across the internet.

It seems almost unimaginable that a single compilation album could sum up a mood, a scene or a movement. Music has fragmented into countless sub-cultures, with so many cheerleaders. Everybody is a DJ and a selector now, from actors to authors to those all-important algorithms.

But way back in May/June 1986, such a thing did actually happen. Weekly periodical New Musical Express, the hipster bible of its time, decided to compile and release another of its regular mail-order cassettes in order to shine a light and focus in on a new generation of artists they had loosely grouped together. Following on from a similar selection five years earlier called C81, the new mix was rather predictably named C86 and advertised in the paper.

Little did the NME or anyone else know or expect, but the cassette went on to become the paper's most successful compilation ever, selling a staggering 40,000 copies. It was then picked up by Rough Trade Records and released on vinyl the following year. Quite some achievement, especially when you realise the uncompromising nature of many of the groups therein, most being relative unknowns at the time.

In that explosive cultural melting-pot of the post-punk 1980s, it seemed anything was possible. By 1986 however, the charts were by and large inhabited by slick mainstream acts sculpted by an industry that yearned for an equivalent to the simple, manufactured pop puppets favoured by the Brill Building and Tin Pan Alley. The DIY ideals and philosophy propagated by the punks and hippies had been quashed in favour of sales and homogenisation. Sound familiar?

As a reaction, the underground dutifully flourished. Electronica, industrial, hip-hop, metal, hardcore punk, goth, reggae and in this case indie-pop went against the grain and created their own worlds. In many ways, what we now know as indie music was actually defined by The Smiths and the bands that made up C86, such as The Wedding Present. Here were the direct descendants of punk, with added optimism, amateurism, surrealism and extremely trebly, jangly guitars. Women were also very much encouraged and applauded for taking part and forming groups. The promise of punk slowly started to manifest itself.

Hair was back-combed, jeans were like drainpipes, long grey anoraks and overcoats were donned, and any kind of dramatic dancing was largely frowned upon. I was 14 years old in 1986 and at the perfect age, being a rebellious, introspective young man. My friend James had the original cassette and we would pour over it in his bedroom, listening to oddballs such as Stump, Big Flame and Bogshed, whilst giggling at Half Man Half Biscuit - all John Peel show favourites on BBC Radio 1 at the time.

Musically, it was odd but it seemed even more accessible than punk to fledgling guitarists like ourselves. If these bands could do it, then anyone could. Scotland's evolving post-punk scene was very much at the centre of the compilation as well. Again this gave us some hope. Very much influenced by the Postcard and Fast Product groups from a few years earlier, The Shop Assistants, Soup Dragons, Close Lobsters, Mackenzies, The Pastels and Primal Scream were all included. The latter two still exist and are releasing some of their best material to date right now.

Tomorrow sees the release of a three-CD box-set of C86 with the original album on one disc and a further two discs containing 50 tracks made up of like-minded peers. Although many of the bands disappeared shortly afterwards, or were simply happy to lurk around the indie charts and enjoy their cult status, the actual compilation itself, its associated aesthetics and haphazard manifesto has helped mark out an entire era. It serves to remind us that almost 30 years later, this gathering of scratchy, angular sounds has had a huge effect.

Scotland and Glasgow in particular has always cherished this music and the setting-up of these independent DIY ideals. To be honest, Scotland could be seen as the indie epicentre of the known world, with Teenage Fanclub, Belle & Sebastian, Camera Obscura, Franz Ferdinand, Casual Sex and Withered Hand all the heirs to the C86 crown. They take the conception forward and breathe new life into it, so blossoming into something original, fresh and vibrant.

If one listens to the independent underground in the US today and many of the artists championed by the international blogosphere, the influence of C86 is hugely apparent. Have a listen to The Pains Of Being Pure at Heart, The Drums, F***** Up and many others for proof. These bands openly admit their love and admiration for that period in music, and for Scotland in particular.

Largely ignored by the mainstream media at the time, the global legacy of artists that have felt the impact from this humble little cassette are still overlooked for the most part. Indie has gone on to mean many things, including bland, sluggish, corporate rock purveyed by oafish boot-boys with a lack of ideas. Although by no means flawless, C86 was none of those things. It may be slapdash and difficult to listen to in places, it may not be aimed at a mainstream market, and it may not be palatable to the judges on TV talent shows; but it's all the more vital for it. Dive in and remind yourself of the excitement of youth and its unbridled expression.

Vic Galloway presents on BBC Radio Scotland at 8.05pm on Mondays, www.bbc.co.uk/radioscotland. Tomorrow he has a live session from Withered Hand. His book Songs In The Key Of Fife is published by Polygon, www.birlinn.co.uk/Songs-in-the-Key-of-Fife.html. Contact Vic at www.twitter.com/vicgalloway