Evergreen notes are notes that, in Andy Matuschak's words, "are written and organized to evolve, contribute, and accumulate over time, across projects," instead of being captured for one task and left behind.
Matuschak sets out the idea on his public notes site and calls it "an unusual way to think about writing notes," because "Most people take only transient notes." He lists principles for the practice: evergreen notes should be atomic, concept-oriented and densely linked, and associative ontologies are preferred to hierarchical taxonomies.
Each principle has its own note. Being 📝atomic means a note is about one thing, captured as completely as possible. Being concept-oriented means organizing by idea rather than by book, author, project or event, so new thinking on an idea combines with earlier thinking instead of scattering across sources. Being densely linked means connecting each note to many others, which he argues makes a writer think harder about how ideas relate and turns rereading old notes into a kind of review; links to notes that do not yet exist are allowed, with 📝backlinks defining the new node.
Matuschak credits the 📝Zettelkasten method as a major influence. He also co-wrote a 2019 essay on 📝Tools for Thought with Michael Nielsen.
In 📝MythOS, 📝the memo is meant to stay revisable and expandable rather than frozen, and links to other memos through mentions.