I dig up free downloads for my readers weekly and there seem to be several main approaches to these ebook giveaways. I often see a limited-time free download of an older book about a month or so before the print version of the next book by the author is due to hit the stores. Presumably this is not to spur sales of the older book, but to spur sales of the new book by letting readers get hooked on an author without risk in the hopes they’ll go out and buy the next book.

Another approach, used several times in the last month by Macmillan imprints is to send out a newsletter allowing a free download of an e-galley about a month or so before the actual book hits the stores. In this case, the goal appears to be to spur word-of-mouth, much like the movie industry has been doing for years by holding showings of movies in select cities before the movie is shown nationwide.

Some give the ebook away for free permanently in the hopes that it will create buzz or spur sales of other books (e.g. an anthology of a magazine, which are usually small runs anyway, might translate into magazine subscriptions).

Some give away the ebook because the book is out of print, but it might spur sales of newer books by the author.

There is no one reason that publishers and authors put ebooks up for free download. Without knowing the marketing goal or the publisher’s measure of success, it isn’t informative to look at print book sales. I think you and the publisher are looking at very different numbers for very different books in assessing the success of this giveaway.