GHOSTS I-IV (Halo 26) and The Slip (Halo 27) were both hugely successful.
And I downloaded Niggy Tardust for free. I did this because I had never heard Saul Williams and wanted to support an artist who I had never heard of. But after listening to it, I honestly just didn't like it, so I did not go back and buy it.
I wonder how many people were like me and downloaded it for free because of the experiment and Trent Reznor's involvement but didn't pay because it wasn't their style of music.