I have to admit I haven’t really looked at this document ever (I can identify most formats quite easily) but was curious as to why some items have question marks after their rarirty?
I’d consider things like CD-R to be common, no question about it - same for Enhanced CD’s.
Also further down, Cassette rarity Common?
I mean surely widespread, cassettes were probably one of the most popular music formats to exist. Out of the top 4:
CD, Vinyl, Cassette and Digital
The wiki can sometimes be misleading as to it’s ‘officialness’. You can totally get stuck in and edit if you think something can be improved!
The page history here features @chaban, @HibiscusKazeneko, @JesseWeinstein and @jesus2099 did some rarity editing, maybe they have some thoughts.
That column is a bit of a can of worms so might not be worth worrying about too much. e.g. cassettes were produced in massive amounts, but how likely are they to be added to the DB?
Interesting stats from a quick goog:
Cassettes: 30 bil
CD’s: 200 bil
Vinyl: couldn’t find
I mean hopefully, very likely! Just gotta find people who wanna do it 
As one of the people mentioned – please, go ahead and remove the “?” from any rows that you think are clear. The wiki is free for anyone to edit.
I feel like im being very dumb, as I cannot find an edit button on that page 
Totally understandable – thank you for asking about it rather than being confused silently! That page is actually the un-editable copy of the editable version, which is linked from the bottom (where it says “This page is transcluded from”). The editable version (once you log in (I think it may be a separate account…)) is at Release/Format - MusicBrainz Wiki
Not sure about that. I think proper releases on CD-R that are eligible to be added to MB are properly indeed not very common. Maybe for small artists who give out self produced CD-Rs. I have one of those.
I’d have to disagree, most (at least in the UK) small-time local artists would have put out their music on home-made CD-R releases. Along with this there are many hundreds of promotional CD’s distributed to radio stations and similar that are also on CD-R.
I mean Discogs has 600,000+ listed in their database already:
If you compare with the amount of real factory CD, it’s peanuts. 
I only have 6 CD-R in my collection: 0.53%
It depends how you source music. Thanks to the MB Collection I have listed of 600 of my CDs I can work it out for my small UK based sample.
I have 4% CD-Rs in my collection from various routes.
That is more than twice as many as I own Enhanced CDs (1.6%), and 10 times more than Copy Control CDs (0.4%).
Many are promos, some are from gigs, others direct from artist releases. A lot from trawls of EBay of something unusual. You also find big bands like The Pixies who will release recordings of concerts on the same night as the gig on CD-R.
The clickly link for blu-spec CD goes into a dead wikipedia page. I would question how “common” they are. I had to do an online search to understand what they were. (Normal CDs created on a Blu-Ray production line by Sony)
Sure but if you then compare the numbers of CD-R’s to say MiniDiscs, then CD-R’s are king.
The big issue here is that “rarity” needs to be established, what are the thresholds for each “class”.
And just because you only have x amount in your personal collection doesn’t then equal is rarity, on that basis I have say about 20 audio cassettes but that doesn’t mean they’re super duper rare.
I’d call CD-R common when compared with other formats. I would ask “how many people have a (legit non-bootleg) CD-R on the shelf?” And then “how many people have a SHM-CD on the shelf”?
I would have thought you’d get more replies that people own CD-Rs.
Maybe a more suitable question is whats the point of the rarity column anyway? It just seems a point of contention - its an opinion, not a fact.
CD-R and recordable cassettes and recordable (opto-magnetic) MiniDiscs don’t really count for many releases.
Most people (including me) have used cassettes and MD for personal compilations.
Not something that counts as an MB release, hopefully.
And most people who have CD-R in their shelves (not my case) are usually straight copies of commercial CD that they borrowed and copied.
Participating (with similar MP3 users) to the decline of the disc market and the fall of artistic revenues on record sales, leading to the shit digital release world we have now.
Copies also are not MB releases.
But demo and promo CD-R, cassettes and recordable MD do count.
But they are fewer than commercial cassettes and maybe equally uncommon as the commercial (optical) MD.
But sure this column is not really needed, and it can never be accurate.
Fully agree. I guess for the column to be useful the criterium should be: how likely is the format I have in my hands to be this given type. That means that the current distribution among MB entries could be used as a guide to fill this column, once we agree on suitable thresholds.
But surely most of these formats have some kind of other way of being identified.
All formats will follow a specific size, and possibly weight, along with identification marks etc.
Usually by branding on the packaging. That’s how I spot them. And CD-R by colour, 8cm CD by size.
Perhaps it can be an aid when you’re in doubt? That’s what the table is originally meant for, I guess.
