Since the early 1990s and the introduction of Linux as a free operating system, more and more open software and file formats have become available, culminating in a commitment from Microsoft, the world's biggest closed source supplier, to support an open file format for exchanging information in document format. Docx is one of their first contributions.

Open file formats such as docx are important because they allow people to share documents even if they aren't using the same software that was used to create the original document. This makes it much easier for clients, business associates, college students, even family letters to be opened and read by almost anyone who receives them.

Docx, is the file extension used for documents from Microsoft Word 2007, which is part of MS Office 2007, and replaces the older doc format which wasn't an open file format and led to a lot of incompatibilities with other word processing applications such as WordPerfect, OpenOffice, and AbiWord.

As you might imagine, if the document file extension isn't capable of being opened and edited by another application, people who need to use documents that are incompatible with the application they use, will be forced to find a common file format that might not allow full compatibility with all of the features of the original application.What is a docx file?

Indeed this was a major problem through the 1980s and 1990s when file formats were not compatible, and users of different applications were forced to save their documents in a plain text format without most of the formatting that makes docx and other formats from word processors so useful.

Despite calls for Microsoft to adopt an open file format, several years passed before MS finally announced plans to discontinue the doc format and introduce docx. Most of Microsoft's major office suite competitors have agreed to support docx in addition to their own formats. Over the next few years docx is expected to overtake doc as the major file format for all users of Microsoft Word.

One of the major advantages of upgrading to docx is the smaller file size, typically a standard one page letter is just 10kb using docx compared with over 100kb using doc. This is because docx is a zipped archive containing only folders and XML files, in fact a docx file can be renamed to zip and then browsed with most file managers.

Additional Reading on Docx Files: