In September 2005, Lorelle wrote what I consider to be the definitive piece on tags vs categories. In 12 years, my opinions have not changed and I still feel her explanation is correct. That said, there is room for improvement at scale.
Her advice boils down to this:
- Categories are a table of contents
- Tags are index words
By this we mean that categories are the high-level, big ticket items, and tags are the smaller, more precise terms. This is, I feel, the heart of understanding the two.
Further down, Lorelle states that at around 25 posts, a tag is ‘big enough’ to be a category, and that if a category dominates a blog, it should perhaps be a separate blog. And that’s where I disagree.
On Beyond Zebra
When she wrote her post, the concept of custom taxonomies was barely a gleam in someone’s eyes. Multisite was still WPMU, and a separate installation. Today we have the ability to add our own taxonomies (either in category or tag styles) and we can create a network of related sites on our own. All we need is a little more technical know-how.
When we add on custom taxonomies, we afford ourselves a new way to classify posts, so to the above I would add this:
- Custom Taxonomies are critical but exceptionally unique index words that must be grouped together
Okay that was long, I know, but a Custom Taxonomy is in essence a new subdivision of your site. You can either make it a new table of contents or a new index … or a combination of the two. It’s a little wild, especially when you factor in custom post types.
Overwhelming Category? Custom Post Type!
Instead of making a new blog when your category gets too large and unwieldy, I would recommend making a new custom post type. If I use my helpful example of LezWatchTV, we currently have three custom post types: Shows, Actors, and Characters.
While we could have made them into posts, and used categories to index them, having them be their own post type means instead of a table of contents, I’ve made an appendix. This gives me access to all the cool WordPress features, like archives and sorting and organization, but it does so outside the realm of posts which restricts crossovers. Unless you’re really clever with cross-related content.
A custom post type keeps it all on one blog, but separates them like your laundry.
Too Many Tags? Custom Taxonomy!
If you find yourself having too many tags, it’s time to consider a custom taxonomy. Again, pointing to LezWatchTV, actors have two custom taxonomies: gender identity and sexuality. While those are the same as we use for characters, by having them separate and only applicable to the actor post type, we are able to give a list of all trans female actors with a click. In other words, we’re using WordPress’s native features.
But if we look at the custom post type for TV shows, we have a lot more taxonomies, including two that are constantly being added on to: nations and stations. Every time a new station airs a show, we have to add it in. And there, as of April 1, we end up having 29 nations and 168 TV stations.
Which brings up the next problem, and one that Lorelle does indeed address, but not the way I would.
When Tags Go Rogue
Can tags still go too large? Yes. Oh my lordy, yes.
Recently I saw a site that used unique tags on every single post. I physically flinched when I realized that.
You see, they had around 30,000 posts and 48,000 tags, and for the life of me I couldn’t understand why until I read the site and looked. For every single post there was a commensurate tag for the post title and the date. After 365 dates they thankfully started to repeat, so you might have 10 posts for the
march-25 tag. Except they weren’t consistent and someone else used
25-march and now you can see the rabbit hole fall into infinity and beyond.
Now that said, I have 168 tags for TV stations, each TV show has one, maybe two if they’re lucky or weird, and some tags only have 1 show listed. Others, like ABC, NBC, and CBS, have around 60. Do I think any of those are ‘too large’?
I don’t. Because the number of 25 posts to a tag only holds up at a smaller scale. With 100 to 200 posts, yes, that starts to make sense. At 600 to 3000 posts, suddenly having 198 posts tagged with “Bury Your Queers” doesn’t sound so out of place. It’s about the percentages, somewhat, and also the use-case.
If I know people are looking for a smaller tag (say they really want to see the 10 shows that have the ‘Fake Relationship’ tag), then for the purpose of this site, it’s important. On the other hand, if only one character was tagged cougar, I might not keep the tag as it’s too small to make the data useful.
There is no magic number of tags to categories to custom post types to taxonomies. It all comes down to understanding the goal of your site, the way users look for data, and what is maintainable to you.
In the case of the site with 48k tags, I would have them delete all the date ones, as well as the ones with the same names as posts, and stick to using topical tags. After all, if a tag is only used once, or duplicates some feature already found in WordPress, it’s perhaps not the best idea.