Shutterstock announced in September 2008 that 60 million image files had been downloaded since 2005, roughly three months after a high-risk but finally lucky analysis presumed a similar approach then.
In their recent press release with respect to the 10-million-images milestone, Shutterstock mentions that it "has delivered over 125 million image downloads to customers since its founding in 2003", which would result in a very high number of downloaded files in this relatively short period (September 2008 until February 2010) of only 18 months. -One of the last official numbers, iStockphoto achieved 17.55 million downloads in 2007.
Both annoncements from Shutterstock as of 2008 and 2010 exclude footage.
While Shutterstock added "40,000 new images a week" in 2008, it´s now up to "80,000" per week in 2010, with a rejection rate of 60%.
The rest about the "industry of imitators" over there.