An intersting aspect of this in the professional world is how digital photography is affecting photojournalism and our recording of history. Photojournalists and editors are deleting images that don't seem to have any value, but they may have value in the future.
A famous example is the photo of Monica Lewinsky hugging Pres. Clinton taken long before the scandal. The photographer who took it says that he was surrounded by other photogs taking the same pics, but because they were all using digital, and he was using film, 2 years later he was the only person who had kept the image. All the digital shooters saw no importance in Monica L. so they deleted the image.