Within each website, participants could see what others at that site had already downloaded. So each of the eight sites functioned as a parallel world, with its own, self-contained top of the pops chart.
The results were illuminating - and depressing, if you want to believe that you like certain songs because they are intrinsically good. In each of the parallel worlds, a handful of songs snowballed into hits, receiving far higher ratings than the others. But in each world, different songs became hits. In one example, a throbbing guitar track by the band 52metro came first in one world and 40th out of 48 in another. People were choosing songs on the basis not of quality but of how popular they already were. "We use the behaviour of others as a shortcut for ourselves,"