I find these ranking not at all surprising. Blackwater Park was the album that truly heralded their coming out of the underground, Damnation is the most accessible thing they've ever done, Watershed and Ghost Reveries, their first two albums on Roadrunner, are neck and neck.
Yeah, BWP at/near the top didn't surprise me.
And yeah, 'accessibility' certainly improves chart position in general, but I was surprised to see it have such an effect on a band whose fanbase presumably cares little for accessibility. For example, Dark Tranquillity's 'Projector', Metallica's 'Load', Amorphis's 'Am Universum', and Dream Theater's 'Falling into Infinity' all fall near the bottom of their respective charts, despite being their most-accessible albums. 'Damnation' completely reverses that trend. That's why it would be interesting to see if all the people listening to 'Damnation' actually listen to any other Opeth albums, or if Music for Nations somehow found an independent audience to market it to. Or, maybe it's just "better" than the accessible albums from those other bands.
I didn't realize 'Ghost Reveries' and 'Watershed' were Roadrunner releases, that certainly helps explain their position. This means I would also be interested to see "dollars spent for promotion" next to each album too...I have a feeling that that one variable could explain all chart rankings with a better fit than any other single metric.
And since I joked about Metallica earlier, here are their numbers, using the same criteria:
At first I was surprised to see AJFA below 'Reload', but then I realized that's not quite right. Unfortunately you sometimes have to massage the last.fm data a bit. There are 3 separate entries for AJFA due to different spellings, so you have to lump those together to get a true picture. I already did this for the Opeth results ('MAYH' and 'MA,YH' are the same album, and one of them had a '(Special Edition)' that got a bunch of listens too). Here is the more-accurate chart, including 'Load' and 'St. Anger' as well:
1 Metallica (11,412)
2 Master of Puppets (8,811)
3 Ride the Lightning (8,282)
5 ...and Justice for All (7169)
4 Reload (5,847)
6 Death Magnetic (5,592)
7 Kill 'Em All (5,510)
8 Load (4,790)
9 St. Anger (2,887)
The one remaining surprise to me is that 'Reload' is significantly ahead of 'Load' (though despite the two albums that fall between them on the charts, they're still closer to each other than 'Reload' is to AJFA). I've never really listened to either album, but I figured fewer people would listen to 'Reload' just because fewer people ever bothered to check it out after being burned by 'Load'. But maybe it actually is the "better" of the two albums?
And in case anyone is wondering, according to the "hive mind", both "Nothing Else Matters" and "The Unforgiven" rank higher than any song on Ride the Lightning.
Yeah, that 'accessibility' effect is a bit different than Opeth's. Every single person in the world heard those songs on the radio for 3 years straight, so even that dumb slut Gina Magadakis from high school has those tracks in her iTunes. Not so for 'Windowpane'.
One other thing to remember about last.fm's album charts is that they unfortunately don't reflect how many people said "I'm going to sit down and listen to album X". Instead, I believe they're a compilation of track-plays, where the plays for each track on an album are summed, and then divided by the number of tracks on that album. That means that an album with a really popular hit and 10 other songs that no one ever listens to can rank higher than a "solid" album with no standouts. For example, the huge popularity of "Fear of the Dark"'s title track pulls that album all the way up to #3 on Iron Maiden's list. Or, since ~8,000 people listen to "Nothing Else Matters" in a week, while only ~1,200 listen to "The Struggle Within", that implies that only ~1,200 people listen to 'Metallica' straight through while 5 times more are just shuffling into the hits.