It was originally a content marketing experiment. We thought we'd rather have 100 people receive a free printed copy of the book and love us for this, than a 1000 people receive ebooks and end up in their trash.

The ROI from the 100 trial worked well, so we decided to try and scale it out to more people. TBD whether we'll see a good ROI from 1000 people, but we hope people enjoy it and like us for sending them a free book!