From the Government Printing Office:
The U.S. Government Printing Office’s (GPO) Federal Digital System (FDsys) has achieved the milestone of 500 million document retrievals. FDsys is a one-stop site for authentic, published information on the three branches of the Federal Government. Retrievals are measured by the number of times content is viewed or downloaded from FDsys. GPO launched FDsys in January 2009 and since that time it has expanded to include 800 thousand searchable titles.