The use of Landsat data has exploded since the USGS began distributing the data at no cost via the internet. In the best sales year, around 25,000 images were sold. The Landsat project has now exceeded that number in a single day.
In fact, the 9 millionth image was distributed on September 1, 2012. It has taken less than 4 years to reach this mark, which demonstrates both the temporal and geographic expansion of Landsat-based research, as well as exposure to new communities that are exploring the 40 years of global Landsat data for the first time.