"We hypothesized that Amazon usage would increase in the month of December and the months leading up to it. In 2010, usage of Amazon went up dramatically in March and continued to stay at that level.
We saw that Amazon usage grew coinciding with the launch of Opera Mini for the Android platform and the iPhone shortly after. Another possibility is that Amazon itself may have become more mobile-friendly. Improved mobile platforms and sites that more strongly consider multiple screen sizes have helped users to further embrace mobile shopping.
In 2010 overall, Amazon usage increased almost every month and was highest in the October to December period. Usage in the United States and Germany grew particularly quickly. For Germany, the number of unique users visiting Amazon.com more than doubled from January 2010 to December 2010, from 3 percent to over 8 percent."
Source: Opera's State of the Mobile Web report, December 2010, published 20th January 2011
Note: Based on mobile users who use Opera's mobile browser