Amazon's sales rankings garner a great deal of attention. This mysterious system, understood fully only by the software designers and statisticians employed by Amazon, is updated hourly. Authors are often guilty of checking the Amazon ranking of their titles on a regular basis as a result and self-published authors in particular seem to spend considerable time worrying about the rankings.
The upshot of this is few individuals are actually able obtain any real, meaningful information from the rankings. How many books have been sold to achieve the current ranking? Have any books been sold? An upward movement in the rankings could mean other books have not sold and dropped in ranking while a given title that moves up either sold a single copy or has sold more copies in the past, causing it to hold its relative ranking. Or is that how it works at all?
Software is available that tracks Amazon Sales Ranking and provides reasonably accurate sales numbers based on the information from Amazon. But does make the rankings as important as authors seem to think the numbers are?
I have come to believe the Amazon Sales Rankings are important to be aware of, not as a measure of sales (since most of my books are published through Amazon's CreateSpace I have accurate hourly updates of actual sales available through my dashboard on CreateSpace) but instead as a potential measure of the Long Tail effect of the Amazon search process.
An examination of books on any given topic will reveal that the books with the highest Amazon Sales Ranking for that genre or topic tend to be the ones that appear on the first page of search results. Since these are the first titles offered to the customer to consider for purchase, they are also the most likely to be selected.
Other factors are believed to be part of the sales ranking process used by Amazon, but nothing beats total sales as far as the Amazon computers are concerned when it comes to the order of suggesting books to customers to purchase.