The official torrent Tracker on The Pirate Bay for the free download includes a message from Reznor himself. He outlines the free materials, including how to request the free PDF. He also gives some additional options for purchasing the additional three albums worth of material in various forms, and even acknowledges the reality that trackers for pirated copies of all four albums will no doubt be hosted along side the official release.
"Ghosts I is the first part of the 36 track collection Ghosts I-IV. Undoubtedly you'll be able to find the complete collection on the same torrent network you found this file, but if you're interested in the release, we encourage you to check it out at ghosts.nin.com, where the complete Ghosts I-IV is available directly from us in a variety of DRM-free digital formats, including FLAC lossless, for only $5. You can also order it on CD, or as a deluxe package with multitrack audio files, High Definition audio on Blu-ray disc, and a large hard-bound book."
So far the release has generated enough interest that online sales through the NIN website have been temporarily suspended due to more than three times the traffic originally anticipated. The servers are expected to be back up within a few hours. Until then, the free download is still available using BitTorrent, and downloads may still be purchased from Amazon.com.