What is Desktop Publishing Software?

In the beginning (1985 to be exact) desktop publishing software was synonymous with PageMaker. Then along came QuarkXPress, powerful word processors, PowerPoint, specialized software for business cards, greeting cards, and even labels all trying to cash in on the desktop publishing revolution by calling themselves desktop publishing software. So now asking "What's the best desktop publishing software?" can elicit confusing and conflicting answers. That's why I make a distinction between page layout software and all those other desktop publishing programs. It doesn't eliminate all the confusion since there are many "levels" of page layout software, but at least we've narrowed the field.