Currently, an overwhelming majority of word processed work on computers is done using Microsoft Office (specifically Microsoft Word). The program is so ubiquitous as to be specifically taught as part of the ICT syllabus in most schools, in spite of the fact that the software is not free or open-source, and creates documents using proprietary formats which do not leave the content in a human-readable state when examined outside of the original software.
Microsoft Office is not widely available to the private user without the purchase of a license. As a result, people are forced to pay in order to be able to use the same word processor with which they were taught. While this may seem something of a small investment when compared to the initial outlay required to buy a computer, a desk or a house to put it in, it is entirely unnecessary and also means that the users' introductions to software are to programs which are expensive and require expensive licenses, amongst other issues. One such issue is that Microsoft Office uses proprietary formats which are not designed to be used by other pieces of software. This also adds to the 'closed' nature of the software and the limitations here are obvious; while certain other programs can open these documents, the latest file formats remain out of reach.
The 'closed' nature of the software chosen by many has even more of an effect on the perceptions of the user because it is very difficult to modify the software to fit the specific needs or preferences of each user. The structure of the program is not accessible to the uneducated user and, since it is one of the main in-roads to computing for so many, does not introduce users to the possibilities of customising their software to suit. As a result, there is no motivation for a 'basic' user to attain an understanding of how their software works.
There are many alternative word processors which use formats which are either non-proprietary or are at least derivatives of other formats. The most common of these is OpenOffice, currently owned by Apache. Like many word processors, OpenOffice is freeware and is open-source, meaning that it can be accessed by anyone and also contributed to and modified by anyone with an understanding of programming. This means that many Some freeware word processors can also open file formats produced by Microsoft's programs (or other 'closed' products), along with producing files in formats which may be opened by a large number of other word processors.
So, does it matter which word processors are used by people? Of course not. As long as the end product may be read by the target audience, the role of the software has been fulfilled. On the other hand, the choice of software used to teach people how to access computers is somewhat more important, as it shapes the impressions made by technology upon the user, and it might not be entirely constructive to give an impression of software as an individual product which must be bought and may not be changed by the user or interact with software which has not been vetted by the original organisation.