Direct Access is an automation tool for Windows. It allows you to carry out actions by typing strings of text. Direct Access recognizes those commands when it is set to be listening for them; it then looks for actions associated to those commands and carries them out.
There are several ways of adding abbreviations to the application. You can either import commands from other applications or create new ones. Whenever you start typing when Direct Access is running, the application will suggest commands for you. You can either accept and carry out those suggestions or ignore them and keep on typing.
As far as I can tell, the abbreviations and the actions serve two main purposes. The first one is launching applications in general. While the second purpose is to paste predefined passages of text to an active application. For example, if you want to use Direct Access as an application launcher, you would just assign the abbreviation "wmp" to Windows Media Player. In addition, you can just use Direct Access as a typing aid by adding abbreviations to strings of text that you use a lot. For example, you can have the application type "To whom it may concern" whenever you type "twhom".
Direct Access also has a lot of options and I am sure the features run deeper than this. So it is up to you to research a little and see how far its potential will go.