From IndieWeb

tags or tagging refers to categorizing or labeling content, your own or others (tag-reply), with words, phrases, names, or other information, optionally linked to specific people, events, locations, such as the practice of tagging posts being about certain people (person-tag), like tagging people or other items where (area-tag) they're depicted in a photo.

Even HTML angle-bracket "tags" are a way to label plain text as having a specific meaning (like a heading or a paragraph), more information (a hyperlink), or some interactive function (like a button).

You might also be looking for:

  • tags page โ€” a page of all the tags in use by a site or profile
  • tag page โ€” page of all the posts with a specific tag


Why tag posts, both yours, and others, and why person-tag too.


Main article: search

Tagging something helps you find it again in the future when you're searching on that topic (the tags you used), e.g. searching on your own site for a subject.


Main article: discovery

Tagging something helps it show up when others search on that topic (either on your site, or on silos via your POSSE copies), and in particular, surfacing that something to people that you know are actively searching on a topic, e.g. like a recent/popular news item.


Person-tagging someone in a post is a social gesture saying publicly that the post is about them, and thus indicating in a (likely) positive way that you're thinking of them.

Person-tagging a photo is a small (likely) positive social gesture that you saw them in a photo and thought of them.

Sharing Interests

Using tags, you can create a tag cloud that aggregates your tags. This can be used by both yourself and readers to see, at a high-level, on what topics you frequently publish.

How to

How to markup

To tag a post, add class="p-category" around the tag name.

For example, a plain text tag:

<span class="p-category">indieweb</span>

Or a tag that links to a tag page on your site, a broader tag aggregation page, or a reference such as Wikipedia:

<a href="/tag/indieweb" class="p-category">indieweb</a>

mark up and post a tag reply

To post a tag reply, the reply post's h-entry MUST hyperlink to the permalink of the thing that is being tagged, with class="u-tag-of". E.g.

<span class="h-entry"> ... 
 Alice tagged 
 <a class="u-tag-of u-in-reply-to" href="http://s.example.com/post47">Some Article</a>
 as <span class="p-category">tag</span>

Adding in an h-card makes it a person-tag. See person-tag for more specific examples.

<span class="h-entry"> ... 
 Alice tagged 
 <a href="http://bob.example.com/" class="u-category h-card">Bob Smith</a> 
 in <a class="u-tag-of u-in-reply-to" href="http://s.example.com/post47">Some article</a> 

IndieWeb Examples

Shane Becker

Shane Becker supports tags on his site (as powered by Dark Matter).

Aaron Parecki

Aaron Parecki implemented linked tags (on 2013-04-21).


Tantek ร‡elik added automatically marked up tag support to hashtags on his posts, implemented 2016-01-25, but first deployed early 2016-01-26 e.g.:

gRegor Morrill

gRegor Morrill added plaintext tags on event posts on 2016-03-09

Added on note posts on 2017-03-19

Marty McGuire

Marty McGuire added linked tag support on 2017-02-20. Tags appear in the footer or header of posts, marked up with .p-category and linked to a tag page.

Eddie Hinkle

Eddie Hinkle implemented linked tags (on 2018-01-01).

Jamie Tanna

  Jamie Tanna has been tagging content since his first post in 2016. He has marked up posts with `p-category` since 2019-03-19.

Jamie also marks up categories as well as tags, but they are mostly hierarchical and there are fewer used

Sam Wilson

Sam Wilson has tags listed at https://samwilson.id.au/tags and each tag can optionally be linked to a 'same-as' Wikidata ID which adds an infobox to the tag overview page.

Past Examples

Kyle Mahan

Kyle Mahan had an old-fashioned list of tags at the end of each post. hashtags that were added inline automatically populate the tag list (so that they will appear twice, once inline, once in the list). (Originally implemented in Red Wind (on 2014-05-09) (on development hiatus), now implemented by using Known).

  • Example tagged post https://kylewm.com/2015/08/updated-woodwind-to-preselect-syndication-targets (needs Internet Archive link)


Main article: hashtags

hashtags - a method of tagging posts merely by prefixing the literal text of the tag inline in the post content with hash or pound character '#'. Popularized on Twitter, hashtags have been adopted on other silos as such as Instagram, Google+, Tumblr, Facebook, etc.

Person Tags

Main article: person-tag

person-tag - tagging a post, often a photo, as being about or of a person.

Private Tags

Any kind of tag could also be made a private tag.

Private Tags - a tag that is only visible to the content creator.

IndieWeb Examples

Sandeep Shetty

Sandeep Shetty uses a #private tag (as a way to reduce an interface element that is required less often) to make posts only visible to him.

  • You can combine Private tags and #private to make both tags and content visible only to the author.

Shane Becker

Shane Becker supports private tags on his site (as powered by Dark Matter).

  • Any tag that starts with a . is only visible to the author when they're signed in (since 2016-11-03)
  • Any private post is auto-tagged with with ".private" (since 2016-11-03)

Machine Tags

Machine tags are also sometimes called triples, a triple store, or triple tags. They come in the form of namespace:predicate=value. And they are typically not written by humans directly, hence the name "machine tags", as coined by Aaron Straup Cope when Flickr implemeted them on 2007-01-24. They are usually added to a post when the post is created/edited by another piece of software via an API.

  • medium:paint=oil
  • geo:quartier="plateau mont royal"
  • upcoming:event=81334

One way to think about them is that they are just like normal tags and treat it as just a string of characters. You can also think of them as normal tags with a prefix:

  • value is the tag
  • namespace:predicate= is the prefix

IndieWeb Examples

Shane Becker

Shane Becker implemeted machine tags on his site (as powered by Dark Matter) on 2016-04-08.

Xavier Roy

User:Xavierroy.com has tagged podcasts with some machine tags for now. He already has some machine tags for his eat, drink, read, and watch posts but they show up only in search right now.

Web Tagging Origins

The mid-2000s Web 2.0 trend popularized free form tagging not part of any formal taxonomy (referred to as a folksonomy), as well as the practice of people tagging (each) others' content in a shared location (AKA social tagging) that could surface aggregate trends. This trend was started in 2004 by various sites (link-tagging silo Delicious (original site since defunct) & photo silo Flickr), blogging tools (e.g. WordPress), and blog search engines (Technorati (2005 tag search now defunct)1).

See Also