Markdown documents
A document is a piece of writing in markdown. It has a title and a body, and a short name used in its address. It carries a marker that says what kind of document it is, such as a doc, a note or a narrative, and it belongs to the workspace it was written in and to the person who wrote it.
Every time you save, the hub keeps the previous version, so a document's history is always there to go back to.
For search, and for a persona to recall it, a document is split into pieces. Each piece knows whether it has been prepared for search by meaning since its text last changed. Search over the body of a document finds whole words anywhere in it, and the recent-activity feed shows what has changed lately.