Zack Evans is one of my oldest friends, a man I have known for almost 25 years now - back in the days of university bulletin boards when he was RAVE CHILD and thus in the best position to pull me up on my ignorance of dance music. To this day he will still pull me up on things, just like he did on Twitter last week when upon reading my last post he noted (on a now-deleted account):

@ChartUpdate "service[s] such as Spotify are close to containing every last bit of popular music ever recorded" - strong words.

Yes, strong words, although in truth probably more a case of both lazy writing on my part or at the very best use of some dramatic hyperbole to emphasise the point I was trying to make. Nonetheless, for any long-time music fan, the availability of vast catalogues of recorded music all of which can be heard at the press of a screen or the click of a mouse can be a rollercoaster experience. For every moment of joy at discovering the presence of songs you had long thought were confined only to your memory (hence the Elaine Paige piece last week) there are indeed some glaring omissions which make you go scuttling back to your physical collections for reassurance.

The most notable digital absentees remain Def Leppard. At one point legitimately the biggest rock group on the planet, you will search the Spotify or indeed iTunes catalogues in vain for albums such as Hysteria, Adrenalize or indeed most of their lesser starred recording released either side. The reason for this is apparently because the group long ago inked a deal which means all rights to their music revert to them 20 years after release. They choose to exploit this ownership of their catalogue by crafting deluxe editions of the old records, making them physical collector's items. They appear to have no interest in moving into the digital age and in the process perhaps facilitating the discovery of their work by new generations. Super-serving the long term fans is their aim, and in truth, they are rich enough not to care about losing out on any other revenue streams. All they have on Spotify then is a live album and the handful of reworked tracks they did for the Rock Of Ages musical soundtrack. However the presence there of their most recent deluxe repackaging, 1996's Slang suggests that possibly all it takes is time and remastered versions of their most famous albums will eventually appear.

Some artists are just wilfully unavailable in all forms. The chances of Spotify and the like ever containing "every last bit of popular music ever recorded" are minimal when there are acts such as the KLF whose entire catalogue has been deleted for over two decades. Virtually everything Bill Drummond and Jimmy Cauty have ever done can be interpreted as a carefully thought out piece of performance art. Their refusal to allow anyone to buy or legitimately listen to any of the work which made them famous in the early 1990s is probably best viewed in those terms rather than being a case of the pair being miserable bastards.

For my part, I remain continually annoyed at the gaps in the catalogue which means I cannot revisit my appreciation of the second album from Material Issue. The power-pop trio's 1991 debut International Pop Overthrow is present and correct on Spotify, but the follow-up Destination Universe is missing, this despite being released by the same label and under the terms of the same record deal. Until someone chooses to throw up a dodgy rip on YouTube it means I can't hear What Girls Want or forgotten classic single When I Get This Way (Over You) and either appreciate it anew or discover that my memory of it is playing tricks.

But that said, for all the above frustrations, Spotify contains the kind of gems which I never dreamed I'd either hear again or be able to get my hands on easily. Elaine Paige's 1991 comeback attempt we've already covered, but there is other stuff as well. For many years the Michael Jackson oddity Farewell My Summer Love was something of a holy grail for collectors. The cash-in 1984 release featured ten-year-old Motown material newly reworked with overdubs to make the songs sound halfway relevant in the post-Thriller era. It had fallen off the catalogue shortly after release. When the singer died in 2009 his entire musical output poured back onto the charts. Yet Farewell My Summer Love remained missing, despite its title track becoming a Top 10 hit in the UK in the summer of 1984. A cassette of the album was presented to me on my 11th birthday to accompany my first ever walkman. I must have played it a hundred times before donating it to my sister (busily building up her own Michael Jackson collection) who promptly lost it.

Yet not only is the album now online in its entirety but there are complete sets of Motown recordings featuring the original untouched 1970s tracks allowing side by side comparison. That's utterly phenomenal.

I also love the esoterica you can stumble across. Many years ago my friend Louis played for me an old Bernard Cribbins LP of novelty songs he had uncovered from one of the many second-hand record shops he would spend his weekends wallowing in. It was the kind of collectable which made searching racks of records such a joy, an all but forgotten gem from the past. Only now his entire recorded catalogue is up on Spotify. And I can play it any time I want.

Every "last bit of popular music ever recorded"? No not quite. But there is more than enough to satisfy for now.