📝 Lesson 2.3: Metadata — Tags, Properties & Aliases

What Metadata Is & Why It Matters

Metadata is a fancy word for a simple idea: data about your note, separate from the note's content. The note's body is what you wrote. The metadata is the labels around it — its topic, its status, when you created it, who it's about.

Think of a library book. The story is the content. The little labels — genre sticker, catalog number, due date, author card — are metadata. You'd never find a book in a big library without them. A vault of a few dozen notes is fine without metadata; a vault of a few hundred is not. Adding light, consistent metadata now is the difference between a searchable second brain and an unsearchable pile.

Tags & Nested Tags

A tag is the simplest piece of metadata: a keyword prefixed with a hash. Type # immediately followed by a word (no space!) anywhere in a note:

Met with the design team today. #meeting #project

Tags turn into clickable labels. Click one — or open the Tags pane (a core plugin) — and Obsidian shows every note carrying that tag. It's an instant, effortless way to gather everything on a topic without moving a single file into a folder.

Nested tags: tags with structure

Add a forward slash to create a hierarchy inside a tag. This groups related tags under a parent:

#project/active
#project/on-hold
#project/done

Now #project is a parent, and the three states live beneath it. In the Tags pane they collapse neatly under project, and searching for #project finds all of them at once, while #project/active narrows to just the active ones. Nested tags give you the organization of folders with none of the rigidity.

You can put tags in two places: sprinkled in the body (inline, as above), or collected in a note's Properties under a tags field (coming up in Section 4). Both feed the same system. Many people prefer Properties for a note's "official" topic tags and keep inline tags for in-context flags.

Tags vs. Links: When to Use Which

Here's a question that puzzles nearly everyone at this stage: if a tag gathers related notes and a [[link]] connects notes too, when do I use each? They feel similar, but they answer different questions.

A rule of thumb that serves most people well:

Use a link when the thing deserves its own note. Use a tag when it's a category or state that spans many notes.

For example, a note about a meeting might link to [[Design Team]] and [[Q3 Launch]] (real things with their own notes) while carrying the tags #meeting and #project/active (categories/status). You don't have to choose one system — the best vaults use both, each for what it's good at. We'll go deep on links in Module 3; this lesson just makes sure you know they're complementary, not competitors.

Properties: YAML Frontmatter

Tags are great for topics, but sometimes you want named fields — a note's status, its author, its due date, a rating. For that, Obsidian gives you Properties, stored in a block called YAML frontmatter at the very top of the note.

Here's what a frontmatter block looks like. It must be the first thing in the note, opened and closed by --- on their own lines:

---
title: Weekly Review
status: active
rating: 5
favorite: true
created: 2026-09-14
tags:
  - review
  - productivity
---

# Weekly Review

The rest of your note goes here, as normal.

Everything between the two --- lines is metadata; everything after is your content. In Live Preview and Reading view, Obsidian doesn't show you raw YAML — it displays a friendly Properties editor at the top of the note, a little table of fields you can click and edit directly. The messy syntax is hidden; you get a clean form.

Why bother with Properties instead of just tags? Because Properties are structured. A tag says "this note is about reviews." A property says "this note's status is active and its rating is 5." That structure is what lets you later query your vault — "show me every book note with a rating above 4" — which brings us to a small preview at the end of this lesson.

Property Types & the Editor

Obsidian understands several property types, and it treats each one intelligently — giving dates a calendar picker, checkboxes a real toggle, and lists a tidy tag-style input.

Using the Properties editor

You rarely need to type YAML by hand. Obsidian's Properties core plugin gives you a visual editor:

• In a note, run the command "Add file property" from the command palette (Ctrl/Cmd + P), or click "Add property" at the top of the note. Obsidian creates the frontmatter block for you if it doesn't exist yet.
• Type a property name, then its value. Click the little type icon to the left of the name to change its type (text, list, number, checkbox, date, date & time).
• There's also a Properties view (in the right sidebar) that shows and edits the current note's properties, and an "All properties" pane that lists every property name used across your vault — handy for keeping names consistent.

Common, well-known properties

A few property names are recognized by Obsidian and do special things — worth knowing so you use them on purpose:

Aliases: Many Names, One Note

People and things go by more than one name. Your note titled "United States of America" might also be searched for as "USA," "US," or "America." Aliases let a single note answer to all of them.

Add aliases as a list property in frontmatter:

---
aliases:
  - USA
  - US
  - America
---

# United States of America

Now two wonderful things happen:

• Search finds it by any name. Search or Quick Switcher for "USA" and this note surfaces, even though its filename is different.
• Linking autocompletes by alias. Type [[USA and Obsidian offers to link the note — and it can insert the link so it displays "USA" while pointing at the real note. No more broken links just because you called something by a nickname.

Aliases are perfect for abbreviations (JavaScript / JS), full-vs-short names (Dr. Jane Smith / Jane), spelling variants, and things that got renamed. They keep your links flexible without ever duplicating a note.

🎯 Project: A Frontmatter Template

Metadata only pays off when it's consistent. In this project you'll design a small, standard set of properties and apply it to several notes — the habit that makes a vault queryable for years.

---
title:
tags:
  -
status: active
created: 2026-09-14
favorite: false
aliases:
  -
---

Best Practices for Metadata

✅ Do's

• Keep a small, standard vocabulary. A handful of consistent tags and property names beats a sprawling, one-off mess.
• Let autocomplete guide you. Reuse existing tags and property names rather than inventing near-duplicates.
• Match the type to the data. Dates as dates, numbers as numbers — it's what makes future sorting and querying work.

❌ Don'ts

• Don't over-tag. Ten tags on one note usually means none of them are useful. Tag for real categories you'll actually filter by.
• Don't put a blank line above your frontmatter. It must be the first line, or Obsidian won't recognize it.
• Don't duplicate a note just to give it another name — that's exactly what aliases are for.

📓 Learning Journal

📝 Lesson Summary

🎉 What You've Accomplished

You've added the invisible skeleton that keeps a large vault usable. You can tag by topic, structure notes with typed Properties, give notes multiple names with aliases, and — crucially — you understand when to reach for a tag versus a link. Most people discover metadata only after their vault becomes a mess; you're building the good habit from the start. That's genuinely intermediate-level thinking, and it will pay off every single day going forward.

❓ Common Questions at This Stage

🔭 Looking Ahead

That wraps Module 2 — Writing in Obsidian. You can now write rich, well-formatted, well-labeled notes. Next, in Module 3, we get to the feature that makes Obsidian magic: internal links and backlinks. You'll connect your notes into a living web and watch the famous graph view come to life.

✅ Before the Next Lesson

• Apply your frontmatter template to at least three notes
• Add aliases to one note and confirm Quick Switcher finds it by an alias
• Write your Learning Journal entry — with frontmatter this time

📚 Additional Resources

• Obsidian Help — Properties
• Obsidian Help — Tags
• Obsidian Help — Aliases