Kindergarten Math Free was published on the amazon market at the end of November.
Amazon’s market is a bit different from the android market. It takes longer to publish the app on the market. It has to be reviewed and approved by Amazon, which can take a week or two. I happened to publish it right around the time Kindle Fire came out as well. Kindle Fire has android based OS, so, it can run apps built for android.
Unlike the google android market, the amazon android market was very slow uptake initially. Then, around 12th of the month or so, it started seeing 30+ installs a day. My theory is that the app got approved for kindle later, or kindle activations kicked in around that time. Installs per day was rising slow and steadily, first to 50+, then 80+, then 120+. Last two days, it suddenly jumped to about 300+ installs. That is considerably more than the google android market downloads for the same day.
My theory is that is a lot of kindle fire christmas presents. People are now loading their presents up with apps. The amazon market also has a dedicated category for kids. It helps people find quality content for their kids more easily. Their recommendations engine also kicks in more-and-more as people download the app. More people download it, then, it shows more often in people-who-downloaded-this-also-downloaded. That drives more sales.
I don’t expect the exponential part of the curve to last beyond the holiday season. Specially, because there are some negative reports on Kindle fire.