Digital mammography sounds like a major technological advance and an improvement over traditional film mammography. But it is really just another way for the mammographer to read the results of a mammogram. It is similar to the difference between a digital camera and a regular one. The primary advantage is the picture can be saved in a computer, which makes it easier to pass on from one doctor to the next.
Because the picture of the breast is digital, it allows the radiologist to adjust the contrast, the brightness, and the magnification of images without additional exposures for the patient. This sounds like it would make mammograms easier to read, but no studies have yet demonstrated any meaningful improvement in the ability to find a cancer with digital mammography.
The one exception to this is women with dense breast tissue. It does appear that digital mammography can detect more cancer in women with dense breasts than film mammography.