Tags and tag groups

What a tag is

A tag is a word written in the text of a page with a # in front of it: #taiwan. It says what the page is about, and it is the only way pages are sorted here — there are no categories to pick from a list, and no separate box to fill in. Write the word in a sentence where it belongs, and the page is tagged.

Readers reach every page carrying a tag at the tag's own page, and the front page lists every group as a row you open to see its most-used tags, with a door to the rest. Pressing a tag there narrows the front page to the pages carrying it; press another and the list narrows to pages carrying both, up to four at a time — a fifth replaces the first. Each row starts with Any, which narrows to pages carrying any tag in that group — so china and the Airline row's Any together are the airlines in China, with no second tag needed on every airline's page. The map's legend has the same Any beside each group. A tag on its own — #taiwan — is a general tag.

Tag groups

Most tags belong to a group that says what kind of thing the word is: a country, an airline, an airport, a year. Write the group first, then a colon, then the word:

#country:taiwan   #airline:china-airlines   #airport:tpe   #year:2019

The same word can mean different things in different groups (#city:taipei and #airport:taipei are two tags), which is what groups are for. The site ships with a set of groups — places from large to small (continent, region, country, state, province, city, place), the aviation set (airline, alliance, airport, hub, aircraft, manufacturer), group for pages that belong together, and person, company, event, year and more — and the administrator can add to the set. The full list is on the site's Tags page.

Grouping pages

#group:china-northern on every page about the China Northern group — the holding company, each carrier, the fleet page — makes /t/group/china-northern the page that lists them all. That is how pages are grouped here: a tag any of them can carry, rather than a page kept under another page. A page can be in several groups.

Tagging a page as a thing

A page about an airline is put under the airlines group by carrying its own tag in its text — #airline:china-northern-airlines somewhere in a sentence — and the same for a page about an airport (#airport:she), an alliance, a person. The tag then lists that page and every other page that mentions the airline the same way. A tag has to be in the visible text: a note hidden inside <!-- --> is removed before tags are read, so a tag written there counts for nothing.

If you write a bare #word and only one group already holds it, the tag goes there; otherwise it is a general tag. Writing the group makes it certain.

How many tags a page carries

A page carries a limited number of different tags — five, unless the site has chosen another number, and staff can give one page more. The first ones written count, in the order they appear in the page. A tag past the limit stays in the text exactly as you typed it: it does not file the page anywhere and is not created, and the editor tells you which ones. Writing the same tag twice counts once, and so does writing it once as #china and once as #country:china.

Spelling and the first use

Tags are matched by their spelling folded to plain letters — lowercase, with spaces and underscores as hyphens — so #Taiwan, #taiwan and #TAIWAN are one tag, and #New York, #new_york and #new-york are one tag. The tag is that folded word and nothing else: however a page spells it, the chip on the page, the tag's own page and every list show #taiwan and #new-york. There is no separate display name to keep in step. The first page to write a tag creates it.

A new tag that looks confusingly like an existing one (a lookalike letter, say) still works on your page but is held back from the front page and from suggestions until staff have looked at it. A site can choose to hold every new tag that way: your page keeps the tag and its page exists, but the word does not appear on the front page, in the suggestions or on the map until a moderator approves it.

As you type

In the editor, typing # and a few letters offers the tags that already exist, in a list just under where you are typing — anywhere in the text — and #country: on its own offers that group's most-used tags. Press ↓ and ↑ to move through the list and Enter or Tab to put the highlighted tag in, or click it; Esc closes the list. Putting in a group (#country:) goes straight on to offer its tags. Choosing an existing tag rather than inventing a near-duplicate is what keeps the tag pages useful.

Under the text box, Tags on this page shows every tag your text writes as a row of chips, with what saving would do with each: how many pages already use it, or new, each chip coloured to match. A tag that would wait for a moderator, and a word that would stay plain text because the page is at its limit or the group does not exist, are coloured too and explained under the row — as is the existing tag a new one looks like, if any. The row updates a moment after you stop typing and saves nothing by itself.

Merging and renaming

When two tags turn out to mean the same thing, staff can merge one into the other. Every page carrying the merged word moves to the surviving tag, and the old word keeps working as a way to reach it, so nothing anyone wrote needs to be edited.

Staff can also rename a tag, and a rename changes the word: renaming globalsky to Global Sky makes it global-sky, at a new address, and the old word keeps working as a way to reach it just as a merged word does — every page that wrote #globalsky shows #global-sky from then on without being edited. A word another tag in the group already holds cannot be taken by renaming; merge into it instead.

A tag that nothing uses for a while is cleaned up automatically. A tag on a page that is hidden or not yet published is not shown anywhere either — a tag never reveals a page readers cannot see.