It's not a Pokemon. Well maybe it is...but we're not talking about the Pokemon right now!!

A Wikitag is a content-type used on LessWrong that combines a wiki-page and a tag into a single entity/abstraction. We think this just makes sense.

Take the concept of Functional Decision Theory. We could separately have a wiki page that explains the concept and a tag that is applied to posts about that concept, but why have them be separate? If the wiki page is also a tag, then we can conveniently list on it all the posts that are relevant.

Q. But it doesn't make sense for all wiki pages to be tags!!

True! And that's why wikitag pages come with a checkbox for whether or not a given wikitag should be usable as a tag.

Some reasons a wiki page shouldn't be usable as a tag:

It's too specific of an idea to really apply to individual posts, e.g. Square visualization of probabilities on two events
The wiki page is more a publicly-owned post than a pointer at a concept, e.g. Open subproblems in aligning a Task-based AGI
The wiki page is redundant/overlapping with another page that is already serving as a tag, e.g. Bayes' rule: Probability form shouldn't be a tag in addition to the main Bayes tag
A wiki page is kind of a "personal wiki page"
other reasons!

The decision for whether a wikitag page should have the tag-component activated or not is easily reversible, so it's not too important to get it right.

When a page is set to "wikiOnly" then:

when viewed, no list of posts will be displayed
when someone click "add tag" on a post and begins typing, this wiki page will not be suggested and cannot be applied to a post
if the wiktag page was already applied to a post (and then "wikiOnly" was set to true), the tag "pill" on the post page will no longer appear

Q. What about tag page that shouldn't be a wiki?

This can occasionally happen too though really for all tags it's ideal for there to be at least a sentence or two clarifying the intended usage, drawing attention to key resources, etc.