Last.fm says no, it didn’t happen, and it’s really upset about the rumor first circulated Friday night by TechCrunch. Last.fm has apparently suffered the loss of some registered users since the rumor hit and is worried about its reputation. The original story was that the RIAA was tracking down last week’s leak of the new U2 album named “No Line on the Horizon.” More here from the Guardian – though note that there’s some PG-rated language here from people at Last.fm, including one of the site’s three co-founders.