Advertising a Free Book, Part 4

Does advertising a free book pay off? A while back, I summarized results of setting When Danger Calls to free, as Book 1 in my Blackthorne, Inc. series in conjunction with the release of Identity Crisis, the 7th book in the series.

You can find those posts here: Part 1    Part 2    Part 3

As I prepared to release Deadly Engagement, the 6th offering in my Mapleton Mystery series, I decided to do the same, setting Deadly Secrets to free. Again, I advertised the free book, using two of the same...