tags

 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 — a page of all the tags in use by a site or profile
 * tag page — page of all the posts with a specific tag

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

Refindability
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.

Surfacing
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.

Social
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 markup
To tag a post, add  around the tag name.

For example, a plain text tag: indieweb

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

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. E.g. ... Alice tagged Some Article as tag

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

... Alice tagged Bob Smith in Some article

Shane Becker
supports tags on his site (as powered by Dark Matter).
 * Implemented tags (linked with ) on 2012-11-18 (private repo)
 * #hashtags in notes are autolinked to Twitter's hashtag search pages using Twitter Text Ruby (since 2012-12-26)
 * Plaintext tags can be added to any posttype in a separate field (since 2015-10-11)
 * Example of tagged post: http://veganstraightedge.com/articles/2016/04/08/toward-an-indiewebcamp-logo-redesign-iterations-in-the-key-of-c
 * Tags are listed in the footer of each post and linked to tag a aggregation page
 * Aggregation pages list all post's tagged with that tag: http://veganstraightedge.com/tags/indieweb (since 2016-03-13)
 * All tags page: http://veganstraightedge.com/tags (since 2015-11-03)

Aaron Parecki
implemented linked tags (on 2013-04-21).
 * linked tags in his posts (specifically, hashtags) to tag pages: http://aaronparecki.com/tag/indieweb

Tantek
undefined added automatically marked up tag support to hashtags on his posts, implemented 2016-01-25, but first deployed early 2016-01-26 e.g.:
 * https://www.flickr.com/photos/tantek/23995162453/ POSSE copy with all "tags" automatically posted by Bridgy Publish which detected them all from the hashtags auto-marked up with u-category on:
 * original: http://tantek.com/2016/002/t2/change-clothing-inspired-tomorrowland

gRegor Morrill
added plaintext tags on event posts on 2016-03-09 Added on note posts on 2017-03-19
 * http://gregorlove.com/2016/01/pink-martini/
 * https://gregorlove.com/2017/03/ooh-unwed-sailor-is-playing/

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

Eddie Hinkle
implemented linked tags (on 2018-01-01).
 * linked tags in his posts (specifically, hashtags) to tag pages: https://eddiehinkle.com/tag/indieweb

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
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.

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)

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
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.
 * Pinboard.in does this with special syntax: tags that start with a period. e.g., .secret_tag. See https://pinboard.in/tour/#privacy
 * Private tags can be used to do POSSE stuff like what Selective Tweets does with the #fb tag, but without having a visible public tag: like this IFTTT recipe that crossposts Pinboard bookmarks to Twitter that have the .twitter private tag.
 * I have a #readlater tag that I would love to have private -Www.sandeep.io 16:37, 11 September 2013 (PDT)

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
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. 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:
 * is the tag
 * is the prefix

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


 * Example post with a machine tag: http://veganstraightedge.com/videos/2013/05/31/backyard-squirrel-buddy
 * Tag page of posts with machine tag "imported:from=vine-co": http://veganstraightedge.com/tags/imported:from=vine-co

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.
 * Podcasts with machine tags displayed. https://xavierroy.com/tag/podcasts/

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).