DAT is a commonly used file extension for saving generic data records. The information contained within a .DAT file depends on the program used to create it, but it will usually be in binary code ...

the .DAT file is the exact same as a .MPG file. if it's for home PC viewing, try re-encoding the file into DivX or ASF using a high bitrate and low keyframe intervals to maintain mpeg-like quality ...

"On my PC, and in my many test cases, WaitList.dat contained a text extract of every document or email file on the system, even if the source file had since been deleted," Skeggs told ZDNet.