The patent, filed in December 2004 and granted on August 4 2009, specifies that this is done using an XML Schema Document (XSD), which contains more information about the document's formatting, and also covers systems that can open the document without using the original word processing software.
Both XML and XML Schema are long-established open standards, designed to do exactly this, among many other functions.
The patent also specifies that the document can contain formatting information such as line, paragraph and page breaks, font styles and sizes, and other standard components of text documents.
Within the patent, Microsoft has included a list of over a hundred references to books, articles, patents and other software that bear on XML usage in word processing.
On the face of it, the patent would appear to cover all usage of XML and XSDs in word processing document, which would effectively leave all other modern word processors - and other software that used their documents - liable to licensing by the company.
This article was originally posted on ZDNet UK.