Almost all the programs on your computer will create, open and manage data files used to perform actions and tasks. These data files will have the extension DAT that stands for "Data" files. Applications such as Corel WordPerfect, SoftVelocity Clarion, Microsoft Visual Studio, Ontrack EasyRecovery, Nero ShowTime, Pitney Bowes MapInfo and Nullsoft Winamp are some of the programs that can create, open or reference DAT files.
There is nothing overly special about these files when needed to manually access on a regular basis to run programs. A DAT file is simply a generic data file that will have binary code or text used by the application. Normally, a DAT file can be opened by the software application that created it if the DAT file possesses binary code. If you happen to uninstall the application, you won't be able to use the DAT file. If the DAT file only contains text, you will be able to view that text on most basic text editor programs.