I think this article should be retitled to remove the word "How" at the beginning, since it doesn't even really speculate how one would go about doing this. It's interesting nonetheless.

Any ideas? Assume that someone decided to harness one of the many click-farms to do automated podcast subscriptions?

I suppose it's also possible that Apple did an ill-advised algorithm change or something that changed the weights very heavily, and the spammers who had been quietly doing their thing for months suddenly all got promoted.