Contact File Extension
Contact stands for Windows Vista contact information file. You have chance to open contact files with Note Pad.
It is XML based information file and includes contact informations. You may see the contact names at top row when you open the file.
The same file extension also used for keeping contact informations with a communication software called Windows Live.
You have chance to open this xml based file with Note Pad application. You should just make right click and select Note pad option by clicking "Open With" part.
What needed to Open Contact file extensions.
Note Pad or free alternatives
Links about Contact file extension