Practically Paperless with Obsidian, Episode 21: Tags in Theory and Tags in Practice (And Never the Twain Shall Meet?)

blank tags in close up photography
Photo by Eva Elijas on

Welcome to my blog series, “Practically Paperless with Obsidian.” For an overview of this series, please see Episode 0: Series Overview.

This episode is less of a “how-do-I” and more of a “how-I-struggle with…” post. I have been working with tags for more than a decade and still struggle with them. I wanted to give fair warning at the top in case anyone is expecting brilliant revelations about tagging notes in Obsidian here.

I can’t remember when I first learned of the concept of tags. As someone who grew up during the personal computer revolution, my approach to organizing information was naturally hierarchical. From my earliest days using computers, operating systems organized files in a hierarchical structure, and it seemed natural to follow that model.

Moreover, my schooling, which from 5th grade on paralleled my experience with personal computers–seemed to encourage a hierarchical form of information organization. Textbooks had tables of contents that were organized by Part / Chapter / Section. We used outlines to plan arguments. School notebooks were organized by tabs (remember Trapper-Keepers?). Even something as unbiquious as TV Guide was organized hierarchcally: by Date / Time / Station. Indeed. the closest thing to “tags” that I can think of were the indexes that accompanied many nonfiction books. Entries in these indexes (which themselves were sometimes hierarchical) spanned the hierarchy of the book itself. That is, an entry for “atmosphere, of Earth” might have references in multiple parts, sections, and chapters of the book in question.

First page of the index of the book The Nine Planets by Franklyn M. Branley, the first book I ever checked out of a library.
The first page of the index of The Nine Planets by Franklyn M. Branley, the first book I ever checked out of the library, and the book that introduced me to science and astronomy,

The best I can say is that my awareness of tags probably came out of the various photo-storage apps and services that began to appear around 2004 or so, a decade after the Internet as we know it began to take shape.

Tags: In theory

These photo apps (Flickr was an early one I recall using) allowed users to “tag” photos with arbitrary keywords. This was a revelation to me. After living in a hierachical box for so long, tags introduced two ways that freed me from that box.

  1. The keywords were completely arbitrary. There was no set list. I could make them up, or choose from words that had already been used.
  2. One was not limited to a single keyword. I could tag an image with multiple keywords, placing it in multiple categories at once.

The latter point especially was important. Hierarchies, by their nature, limit where you can place something. A photo, for instance, can be placed in a folder path called /Family/Trips/Italy, or in /Buildings/Cathedrals. To put the photo in both places requires duplicating the photo file and then maintaining it in both places. Tags compliment the hierarchy, allowing one to tag a photo as “Italy” and “Cathedral” simulatenously, without having to duplicate the file.

There was another dimension to tags that I found interesting: crowd-sourcing. Because I first discovered through Internet services like Flickr, tags were often crowd-sourced, meaning anyone could apply tags to photos, thereby creating a kind of public melange of the categorization of images.

At the time, I remember thinking how useful it would be to have the ability to artitrarily tag files in a file system. MacOS introduced such a feature in OS X 10.9 in 2013. When that happened, however, I didn’t jump on it and start tagging my files.

The problem for me was that tags seem like a great idea in theory, but are much more difficult to implement in practice. I discovered this in my first concerted attempt to use tags — back when I was writing my Going Paperless series for Evernote between 2012-2016. Evernote allows you to tag notes with an arbitrary number of user-generated tags. When I began using Evernote (around 2010) I did what I suspect many users did: I started tagging everything without a whole lot of thought about it.

Tags: In practice, a.k.a., by intuition

In practice, tagging has been tricky for me: a classic case of having enough rope to hang myself. It turns out that, for me, at least, tagging comes with the same problems as hierarchical organization: if you just start arbitrarily creating tags, you create a mess of confusion that it is difficult to escape from. Escape is difficult because the process is self-perpetuating, and once started, I find I’d rather go with the flow than to start over from scratch.

What is needed for tags is some kind of taxonomy: a set of rules to follow for when to apply tags, when to create a new tag, and how tags relate to the information they are organizing. Here, however, I come up against a limitation of personal knowledge and experience: I am not a researcher, nor do I have expertise in subjects like library sciences that might provide some kind of guidance in the development of a useful taxonomy for tagging. Ultimately, I am tagging by intuition, which is probably not the best approach.

So back in my Evernote days, I began to think about practical ways in which tagging fits into my note organization, and from that thinking.

1. Tags can span hierarchies

Hiearchical organization can be useful because its very structure provides a map for locating something. I discussed the practical utility (for me) back in Episode 18, when I talked about how I use folders to quickly locate Maps of Content notes. The main limitation to hierarchies from my vantage point is that a note falls into only one path.

Tags can span hierarchies. If you imagine folders and tags as two dimensions of a grid, then the organizational model of notes would look something like this, where folder hierarchies cross horizontally, and tags (in this case, notes tagged “#jamie”) slice vertically across all folders.

an illustration of hierarchical folders show on a horizontal axis and tags shows on a vertical axis

Tags, therefore, compliment hierarchies by allowing you to create categories of notes that span multiple hierachies. In a practical sense, this allows two quick ways of finding a note or collection of notes: by either following a path in a single hierarchy, or by tag for specific collection of notes that span multiple paths in a hierarchy.

2. Tags can be used to quickly identify an arbitrary collection of notes that have a practical everyday utility

I frequently have to find a note related to a specific person. Kelly might ask, “Do you have Grace’s 4th grade report card from the spring?” Or maybe I need my son’s “School Health Entrance Form” for a camp application. One practical arbritrary collection of notes, therefore, is to tag notes by person. I do this way many notes, and these notes often span multiple paths in my folder structure.

This kind of tagging allows me to quickly locate all notes tagged “jamie”, for instance no matter where they are located, and then quickly whittle those notes down to the specific note I am looking for by adding additional search criteria. In the above illustration, the tag #jamie serves as that arbitrary collection of notes.

Similarly, I use tags to identify document types: forms, statements, correspondence, receipts, confirmations, etc. Again, the documents themselves may be spread throughout a file structure, but if I am looking for all school-related forms for my daughter, Grace, then my search would begin with notes tagged “grace” and also tagged “form” — from that result set, I can quickly locate the specific forms in question, regardless of where they are in the file system.

3. Tags can be placeholders for future ideas and concepts

I’ve also found tags useful as placeholders for future ideas and concepts. I described one of these uses in Episode 20, where I illustrated how I tag task lines in my daily notes files with the “post-idea” tag for ideas that I want to write about here on the blog. I then use the dataview plug-in to collect all of the “incomplete” tasks with the tag “post-ideas” in a query that lists the open ideas in a single place.

image showing a checkbox list of blog post ideas, rendered using the dataview plugin and filtered by the tag "post-idea"

There are also subjects that I have a broad interest in, and I’ve taken to using a tag/sub-tag model for captuing notes related to these interests. A few examples include:

  • theme/theory-of-notes
  • theme/theory-of-work
  • theme/value-of-reading
  • sports/baseball

This provides a quick way for me to collect notes together around a theme or concept that I am interested in.

Tagging problems I still struggle with

Despite these practical uses, I still feel like an amateur when it comes to tagging, and no doubt this is reflected in my tag structure in Obsidian today. Indeed, just looking at my list of tags in Obsidian makes me cringe a little. It still feels too arbitrary.

There is a time investment required to tag a note, but at the time I tag the note, it is not clear whether or not there is a clear return on that investment of time. Adding a bad tag is worse than adding no tag at all because time invested to add the tag is either wasted or, worse, does not help in locating the tagged document later on.

Another problem is that, intuitively, I feel that I should be using the fewest tags required to find what I am looking for. And yet tags, like rabbits, seem to proliferate faster than I can wrangle them in.

All of this points to a lack of taxonomy. A clearly defined taxonomy provides a scope for tagging, and more importantly, removes any abiguity from the tagging process. In other words, there is no confusion between two tags, no flitting about wondering, should I tag this note using tag A or tag B. It is always clear from the taxonomy how best to tag a note. But a taxonomy requires knowledge and experience that I don’t have, and this comes to the crux of the tagging problem that I struggle with today:

I don’t know enough about what I need to know to define a useful tagging taxonomy.

I have started to tackle this problem using sub-tags to try to identify those areas of interest I want to collect, but even this seems tenuous at best. It is an ongoing process, and the better handle I have on what goes into Obsidian, the better chance I have of coming up with a reasonably useful taxonomy in the long-run.

For now, my biggest take-aways when it comes to tagging are to ask myself the following questions when tagging notes:

  1. Does this tag help to locate the note or collection of notes that it takes?
  2. Is this tag clear enough that I will remember it in the future without much thought?
  3. Is tagging this note absolutely necessary? Can I find this note easily without a tag?

Outside of some simple, practical use cases that I’ve outlined above, I’m still wary of tags, and yet, ironically, I use them more than I should. I’ve been doing this for more than a decade with only small hints toward a useful taxonomy. Finding the taxonomy that works for me will be the information-theory equivalent of the pot of gold at the end of the rainbow.

Prev: Episode 20: Experimenting with the Dataview Plug-In.
Next: Episode 22: Daily Notes Revisited: The Best of Both Worlds?

Written on March 7, 2022.

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  1. Yes! I have this struggle too. Then the perfectionist in me gets annoyed that I’m not consistent with the tagging. Bryan Jenks video on the differences between links and tags in Obsidian … i think is one way to approach it. I’m just not that disciplined.

  2. My approach to tagging, before Obsidian, was to always tag with What, Who, Where and When. This sounds kind of similar to your example of your daughter’s report card.

    For example, to find my Covid vaccination certificate I knew to search for #Certificate, #NHS and that would get me close enough. I would also add general ‘area’ (of my life) tags like #Health or #Finance. Finally, for something like my vaccination certificate where there was an ongoing topic I would also add a topic tag such as #Covid19.

    I did find this somewhat useful but also found it slightly laborious to keep up. Thus far I have not used tags in Obsidian but if somebody could convince me why I need them I would be open to it 😄

  3. In a recent post on the blog here, you shared a screenshot of a note with the tag “fleeting.” How do you use that tag?

    The distinction of tags crossing folder hierarchies is a good one.

    Are you familiar with DevonThink? They have a concept of “replicants”–similar to symlinks, they allow a document to live on two or more places in a folder hierarchy. In DevonThink folders become like tags. DT also has tags.

    WordPress supports both tags and categories. I spent hours researching the difference between the two, and came to the conclusion there basically is none. Some people like categories, some people like tags.

    I have found one great use for tagging in Obsidian, and I don’t remember consciously deciding to use it. I just started doing it. I use a tag to mark a particular paragraph or block of text. For example, I have a weekly 1:1 meeting with my manager; if I think of something I want to bring up with him, I add it to my daily note, tag it with his name, and then when it’s time to get ready for the meeting I search on the tag and compile meeting preparation notes.

  4. I want to move hundreds of highlights from Readwise into Obsidian. This is my second attempt. After my initial attempt, I realized I needed to restructure my tagging system in before I make the move. This article helped. I’ve tagged and reworked systems in WordPress with tags and categories. I have three questions.
    Before I import my Readwise notes, should and can I build a hierarchical system In
    Can I import by tag?
    What do I do about a child tag that in my mind, has two parent tags.

    Thank you for your writing. I’ve watched YouTube and read articles on Tagging and Obsidian. I’m 75 years old and self taught. I have an almost innate superficial understanding systems and databases. But the vocabulary and processes of today are beyond my aging brain.

    I’m retiring for the second time.

    continue to read it. .

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