LastFm has denied reports that it shares data on who plays what music with record companies. The allegation surfaced about a week ago in reference to reported information on an unreleased U2 album. It seemed to me that LastFM would certainly have knowledge of the type described. The assumption being that anyone playing such music must have obtained it illegally. It seems very plausible that LastFM would have data linking individual users with specific songs played. The issue is whether these data would be shared. LastFM has asked users who cancalled their accounts to consider reinstatement.
A more enthusiastic denial.