What is it about a record label that makes it the sort of place you want to spend time in? When it first emerged in the 1980s, 4AD felt like one of the most enigmatic worlds, the sort of label that you wanted to collect, that brought a sense of "brand loyalty" way before it occurred to anyone to talk about music in such crass terms. I'm sure it isn't just the friend in the year below me at school who could reel off not only B-sides and bass players – but also gnomic strings of actual catalogue numbers: "CAD703. BAD501. CAD809" (all great records, by the way).

Credit for its identity must go to original label boss Ivo Watts-Russell who signed Cocteau Twins, Xmal Deutschland and the Wolfgang Press in the 80s, and then followed with Pixies, Throwing Muses, Ultra Vivid Scene and Lush into the 90s. Arguably just as important to the label's cohesion was designer Vaughan Oliver and photographer Nigel Grierson whose covers gave 4AD its distinct, haunted, painterly quality. It felt like you were peeking into a carnival full of beautiful freaks who didn't want to be seen.

It was also Watts-Russell who had the idea to form This Mortal Coil, a kind of 4AD supergroup with a rotating cast and a commitment to experimentation, whose version of Song To The Siren is arguably the most 4AD thing ever: Cocteau Twins' Liz Fraser in "sings some actual words you recognise" shock, backed by Robin Guthrie's glassy guitar, like someone strumming a church window.

Ironically, the label's biggest hit was the least 4AD-sounding of all. 1987's Pump Up The Volume by M/A/R/R/S, was a global No 1, the result of a collaboration between 4AD's Colourbox and AR Kane.

Current 4AD head Simon Halliday continues to expand the territory mapped out in the past. This week, Grimes's indie helium-pop joined dancier acts such as Zomby and Joker, on a roster that includes St Vincent, Bon Iver, tUnE-yArDs, Blonde Redhead and TV On The Radio. "There's a big gap between Pixies, Dead Can Dance, Cocteau Twins," he says. "The variety then gives me the confidence to be eclectic now." When pushed to identify what makes a 4AD artist, he says "it's hard to quantify" and defers to a conversation he had with Beans from Anti Pop Consortium who described their signings as having "a certain class".

On the horizon in 2012: albums from Ariel Pink, Scott Walker, Twin Shadow and Efterklang, plus new acts including "a hip-hop Ariel Pink" and a Canadian band who sound "quite gothy, ethereal – a bit 4AD in a way – even though they had no clue about us!" There aren't any plans for a new generation of This Mortal Coil – why replicate the past? – but as Ariel Pink, St Vincent, Deerhunter all know each other, there's a possibility of collaboration. At the heart of the label, he says, it's a "balancing act between intention and accident" – still a great place to be.

4AD records - a label that's still made with love