It is a collection of Notes and connections between Notes. Notes can be about anything -- schedules, plans, studies, sketches, feelings. Connections can be of whatever kind the user has words for: This is one of those, this requires that, treat this the same as that, ask so-and-so about this, do this by then, this could help me explain that ...
Each thing can have as many connections to anything else as reflects reality. Indeed, more.
Connections can be classified and grouped together. This allows simplification -- just like using folders to separate many papers into fewer groups. (In fact, if paper could be in more than one place -- quantum paper -- then paper and folders would be equivalent to Semantic Synchrony.)
Connections are used to construct the view the user wants. If I want a list of everything my baby requires that I cannot afford, it is in principle automatically discoverable, and already manually discoverable, if the data is in the graph.
The lists you make can overlap.
Writing into a knowledge graph is only slightly more difficult than writing something on paper. The key difference is that to put it in the knowledge graph, you have to connect it to something else. (Actually you can make disconnected things, but the resulting data is difficult to navigate -- a system equivalent to scraps of paper in a suitcase.)
Graph databases can handle a lot of text fast. On a cheap 2014-era laptop, most views of a graph with more than 400,000 Notes are generated in less than ten milliseconds.
Knowledge graph is an inclusive concept. Google and Siri use knowledge graphs. A mindmap (bubbles and arrows on paper) is a knowledge graph. Some knowledge graphs are hard, requiring the user to record information in prescribed ways, using a prescribed vocabulary. Semantic Synchrony offers what is both the simplest and the most general kind of knowledge graph: it can hold whatever you have words for.
The Semantic Synchrony data model is becoming more general. Initially the graph was a collection of plain text notes. Now git repositories can also be data sources. We intend more generalizations -- images, equations, nonlinear audio and video, ...
Organizing, studying, writing, and planning. Collecting, quickly traversing, and selectively sharing notes.
Trees generalize (flat) lists, and graphs generalize trees, so you could use a knowledge graph for anything you might use a list for. Semantic Synchrony integrates with google chrome, so surfing the graph and surfing the net are a unified experience.
So far, Semantic Synchrony users need not commit to any fixed ontology; they can invent categories as they see the need arise. It is no replacement for git, but it will let you construct and view treelike representations of the data's git history.