This is definitely the question. What is DNG? DNG stands for Digital Negative Graphic. This format has been developed by Adobe Inc. in order to minimize RAW image incompatibilities. Camera manufacturers have proprietary formats for their RAW image. Nikon, Canon, Sony, etc. all have their own proprietary way of creating RAW image files in their cameras. Also these formats change and develop as new models arrive on the market. This could lead to a problem where old RAW images are not supported by software and are not viewable anymore, or old software cannot read the new RAW format from new cameras.
So Adobe created a new format called DNG. Adobe would like this format to become a universal standard like PDF, but so far it is too early to tell in my opinion. DNG format does not differ from RAM created by the camera. There are a few advantages to this format. Any editing of picture properties like exposure, sharpness, etc. are stored inside the file, instead a sidecar XMP file. Although the RAW file format is getting better with compression, still DNG files are smaller. Comparing RAW images created from Canon Digital Rebel XTi, to a DNG file converted in Adobe Lightroom, the DNG is about 2MB smaller. DNG file has all same properties as the RAW file. Also it is an open format, well documented by Adobe, and easily added to any image editor via the free DNG SDK
Now the question is do I DNG my RAW images or not. Some people convert their RAW files to DNG, and backup the originals on a DVD, leaving DNG versions to work with. Some completely ignore DNG format stating that it is too new, and not a standard yet. Preferring one less step in the digital workflow.
If Digital Negative Graphics becomes a standard, it would solve a lot of problems with RAW image import. Right now there is no clear winner. RAW formats are as proprietary as the cameras that create them, and DNG although a good idea, too new, and not supported by all image editors. Since I primarily use Adobe Lightroom and Adobe Photoshop in my digital workflow I will try DNG, and see if that extra conversion step is worth it. Your milage may very.