Doc extension is associated with Office document - Dot. You should install Office pack to open doc files.
Doc extension stands for rich text file which written by Office. You have chance to open doc files with Office Word. You are not able to download Office Pack via internet in this case, you should get a Office Pack cd to install.
The differences between DOT and DOC : Dot file is an empty template. It stands for sample file. On the other hand doc is text filled document file.
Besides, these file formats can be opened by Office type of software called Open Office which can be downloaded free via internet. If you need to open doc files on Macintosh computers, you may take a look to following links.
What to use DOC
which page related to DOC file
DOC Related Searches
You can check related links about DOC fileextension.