Progressive Summarization

Progressive summarization is a note distillation technique from Tiago Forte's Building a Second Brain. Instead of organizing notes through tags or folders, you compress them in layers over time.

Each time you revisit a note, you add one layer of compression:

1. Layer 1 — the original captured text (excerpts, highlights from a source)
2. Layer 2 — bold the most important passages
3. Layer 3 — highlight within the bold
4. Layer 4 — write a brief executive summary at the top

You never do all layers at once. Each pass happens when you naturally encounter the note again — while working on a project, searching for something, or reviewing your notes. The work is "opportunistic, a little bit at a time."

The result is a note that works at multiple reading speeds. Someone (including future you) can read just the summary, scan the highlights, read the bold sections, or dive into the full text depending on how much time and context they need.

Forte frames this as "time travel" — you're packaging knowledge for a future version of yourself who won't remember why this note mattered.

The approach trades off depth of organization for low friction. There's no tagging system to maintain, no hierarchy to restructure. The note itself carries its own distillation. The downside is that notes you never revisit stay at layer 1 forever — the system depends on repeated contact with your material.

This contrasts with approaches like Zettelkasten, where atomic notes are linked and organized at creation time, or the llm-wiki-pattern, where an LLM distills sources into structured pages in a single pass.