I know from personal experience that Maiden fans can raid internet polls pretty rabidly. I was in the Maiden fan club for a while, and there was some random battle-of-the-albums type contest on some random website, with Powerslave being a contender. Even though it was an arbitrary contest, it was taken very seriously on the fan club forum. I remember when Powerslave went up against Moving Pictures, and Rush was kicking Maiden's ass in the poll, so Maiden fan club members started voting repeatedly to ensure they wouldn't lose. One guy voted for Powerslave more than a hundred times.
I realize that this kind of cheating probably isn't possible on Facebook, but I still doubt that this result came about without Maiden's entire Facebook community shouting 'UP THE IRONS' and rushing to cast their vote.