"Sites such as the infamously inaccurate VGChartz put the total sales around 3 million sold to date. However, even this number is grossly inaccurate because the site stops counting sales for different regions at different times for different platforms. I would estimate that the Xbox 360 probably sold around 2 million units, PS3 around 1.6 million units and PC around 1 million units.
With such a large install base on the PS3, would Bethesda Software miss the opportunity to sell DLC on the PSN? Considering that Bethesda Software has put DLC on the PSN before with the previously released Oblivion it makes sense that the company would do that again."