Microsoft Office Word 2007 has incorporated four new file name extensions, along with the other Office programs. Microsoft Word now saves files either as .docx, .dotx, .dotm or .docm. docx and docm are XML file extensions that either do (.docm) or do not (.docx) contain macros. Dotx and dotm are templates that do (.dotm) or do not (.dotx) contain macros.
There are a few benefits to these new Open XML formats:
- The files are automatically compressed using zip compression, making them up to 75 percent smaller than they used to be.
- Another benefit is the improved damaged file recovery feature. XML files keep different types of data separate from each other, allowing them to be opened even if one part of the file has become corrupt.
- You can now more easily detect if a document has a macro in it. File extensions with an X in them can not contain a Visual Basic for Applications (VBA) macro or an XLM macro.