I don't think so. Look at Kanye West: http://www.last.fm/music/Kanye+West/+charts?rangetype=week&#...

Monster should be in place 3 with 14,757 listeners. Instead it's in places 12, 16, 27, and 61. It was a top 20 track for some number of weeks, but it didn't show up in the top 20.

In fact, checking the chart now it seems that that particular problem has cleared up.

I'm not sure what you're referring to. I've never seen this problem clear up.

Also, artist disambiguation is a _hard_ problem

I understand that, and I'm not criticizing that. I'm just pointing out that Pandora is making an effort to work on that hard problem while Last.fm ignores very easy problems. Specifically the easiest problem: albums in which all the track names are wrong because they all have "Explicit" or "Album Version" or some other string appended to their names.