I read Indie author’s blogs about the lack of sales in the past months. Most Indie authors have only been through one or maybe two holiday seasons. A book is a product. Just like with most products there is a sales cycle on a year to year basis.
This sounds pretty straightforward, but with the recent rapid increase in the quantity of e-readers, Anthony describes a sales cycle still trying to settle back down into a regular flow:
The digital book sales for the 2012 holiday was different. People received a lot of Kindles/Tablets under the tree. The only problem was that they had no books on them to read. The result was a Christmas sales season that happened in January, February, and March for eBooks. This was very reminiscent of the PC computer days of the 80’s and 90’s. Families would get PC’s under the tree and then would have to go out after the 25th to purchase software.
If you are a self-published author wondering where all your sales have gone, it's worth having a read of the rest of his analysis. It's a nice summary of sales cycles and anomalies, something an experienced bookseller would already know, but which is probably news to you (as it was to me).