Wiki was the first of many tools providing user-generated content serving diverse applications. Most since the first improve on aspects but fail to be better at hypertext. We consider here why that might be so and how this new wiki is different.
The web was designed to serve authors and readers but the rush to build graphical browsers left authoring, the more creative activity, behind. Wiki saved hypertext authoring by stretching newly introduced cgi forms beyond their intended purpose.
The parade of tools to followed all devised more clever mechanisms for editing and offered their unique schema for structuring content. But not one made an improvement on the hyperlink. Why would they? The hyperlink sends the audience someplace else. Don't do that. This is an attention economy so why give attention away?
# Application
Programmers wield immense control over how computers work. If you want to apply a computer to your work you might look to programmers to make an application that understands your work and brings the computer's speed and memory to bear on your behalf.
The more the application programmers know about your work the more they can automate rote activity reducing it to button presses. We'll call the knowledge they encode the 'schema'. Their applications help so long as the work is within their schema.
Application programmers aspire to know more about your work. The business that hire them hope to own some of your work. The schema of your work becomes their intellectual property. You buy from them the ability to continue your work. This works in the short term.
# Evolution
Our work changes. A schema that applied one year constrains the next. The fortunes of application businesses wax and wain. This is a well studied process that includes concepts like cash cows and cannibalism.
If we are to have any division of labor we have to let some creatives specialize as programmers. They will struggle to understand our work and offer us their schema. They will also struggle to understand the economic landscape within which they work. If they have bosses to please, their schema will serve them too. From this we find the essential conflict of interest.
Adam Smith imagined that providers would adapt to the needs of consumers and that the division of labor maximized wealth for all. Its a nice balance.
But when we talk about computer applications we must ask, can the schema embedded within that application evolve with my work so as to not constrain my own success?
Imagine the limit case where your work has been reduced to a single button, 'do my job'. How can you believe it will do your job tomorrow?
# Hypertext
The 'hyper' has been borrowed from the study of geometry in higher dimensions. A hypercube is a cube in higher dimension. If you follow along the cube's edge, when you get to a corner, you find you have more than two more edges you could follow. wikipedia 
Hypertext is then text, words assembled to have meaning, with choices, many choices, of what to read or write next.
The world-wide web extends this notion to span the internet which already spans the globe. The early web programmers understood that this was an exceptional confluence of technologies.
Built on the twin accomplishments of word processing and internetworking the web server/browser was finally an application that could evolve as fast as the work of those who use it.
See Roy Fielding on REST where the web is reduced to its essential elements by a programmer who helped build it.
"Most software systems are created with the implicit assumption that the entire system is under the control of one entity, or at least that all entities participating within a system are acting towards a common goal and not at cross-purposes. Such an assumption cannot be safely made when the system runs openly on the Internet."
# Federation
The web introduced a format for text that included choices, links to other texts from other places, that might be useful to the reader.
Wiki simplified the web's native hypertext format such that it could be authored in a form built with mechanisms intended for more schematized applications. From this the world's largest single content repository has been built.
Wikipedia.
But even Wikipedia now suffers from its inability to evolve its schema, as simple as it is, along with the progress among its users.
We've disassembled wiki to its essential elements and reconsidered each as cooperating, evolving, independently owned and charitably operated network services. We've taken a big step, just like word processing, internetworking, world-wide web and the original wiki before us.
See Biological Inspiration for reflections on our other source of insight.
We simplified every part as we must if this new wiki is to be understood within the environment of application programming. This leaves some rough edges that highly schematized applications smooth. But we're making something that can outlast every other. That is our accomplishment.