How do I write a good tag wiki?

Please see Jeff Atwood's blog post, "Redesigned Tags Page", which explains the purpose of tag wikis and what a good tag wiki should contain. In particular:

Here’s a few words of advice on writing tag wiki excerpts:

1. The excerpt is the elevator pitch for the tag. You only have ~500 plain text characters for the excerpt, so don’t feel obligated to cover everything in it! Save that for the 30,000+ character Markdown tag wiki. The excerpt should define the shared quality of questions containing this tag—boiled down to a few short sentences.

2. Avoid generically defining the concept behind a tag, unless it is highly specialized. The “email” tag, for example, does not need to explain what email is. I think we can safely assume most internet users know what email is; there’s no value in a boilerplate explanation of email to anyone.

3. Concentrate on what a tag means to your community. For “email” on Server Fault, mention the server aspects of email including POP3, SMTP, IMAP, and server software. For “email” on Super User, mention desktop email clients and explicitly exclude webmail, as that would be more appropriate for https://webapps.stackexchange.com.

4. Provide basic guidance on when to use the tag. In other words, what kinds of questions should have this tag? Tags only exist as ways of organizing questions, so if we don’t provide proper guidance on which questions need this tag, they won’t get tagged at all, rendering the tag excerpt moot. Think of it as a sales pitch: in a room full of tags screaming “pick me!”, what would convince a question asker to select your tag?

5. Some tags are common knowledge. Most tags require a bit of explanation in the excerpt, even if it’s only 3 or 4 words. But if the tag is common knowledge—that is, if you walked up to any random person on the street and said the tag word to them, and they would know what you were talking about—then don’t bother explaining the tag at all. Stick to usage of the tag within your community in the excerpt.

In addition to the above, outstanding tag wikis on Stack Overflow often contain:

• Detailed tagging advice, as well as a discussion of related tags.
• A curated list of links to relevant resources (official documentation, books, articles, tutorials, how-to guides, etc.).
• Selected "FAQ"-style questions for the tag.
• Other detailed, but general, technical information.

A few select examples of high-quality tag wikis are:

• c++
• x86
• c#
• python

How do I avoid plagiarism when writing tag wikis?

Writing good, original tag wikis takes effort and is time-consuming. There has been much discussion on Meta about plagiarism in tag wikis (1, 2).

What constitutes plagiarism in a tag wiki? Is it okay to use content copied from another site, and simply add a link back to the original site/source? How should copied content be formatted?

Original is Best

I am sure many tag wikis are written in good faith, but there needs to be some guidance on how to do so.

In an ideal world, if you are not writing an original tag wiki, then do not suggest the edit. Within the pool of talent on SO there would be many capable people who can author original tag wiki content, it is a matter of encouraging people to do so and discouraging people to copy and paste content. Any original work on the site, as with posts, then falls under the licencing conditions of the site.

Whilst the preference is to have tag wikis to be original content, there are still many tag wikis being suggested that contain copied content. Frequently this content is copied and pasted with a link to the original site, but not formatted correctly.

When using content with attribution it's important to make it clear which part of the content is being copied and the way to define this is with the use of quotation marks or quotation mark up.

Plagiarised Tag Wiki Content

Unattributed content

For example, this tag wiki wiki history:

The original wiki edit used content from another site without any link to the original site. The gives the appearance that the content is the original work of the editor. This is plagiarism.

Incorrectly formatted attributed content

For example, this tag wiki history:

The original wiki edit did provide a link to the original site, but none of the copied content is quoted. As it stands this gives the appearance that the editor is the author of the content and is providing a supplementary link to another site. (I am not suggesting this was the editor's intention!) This is plagiarism.

Correctly formatted content

There is no hard and fast rule of how to format copied content in tag wikis, the aim to clearly demonstrate whether the content is the original work of the wiki editor or from another author.

Quotations

Using the previous example:

Any lengthy portions of copied content from the original site needs to be included within the quotation mark up with a link and description of the original content. In this case the original content is in the documentation at the github repo, in other cases the actual name of the site may be preferable.

With tag wikis that consist only of lengthy quotations, I prefer to add a sentence stating where the content is being sourced from, rather than including a link within the quotation as demonstrated in some examples further down.

So the resulting effort looks like this:

Mixed content

The following example has content that is paraphrased from a site and also quoted from that same site. The first two paragraphs are paraphrased, there is enough similarity between the wiki content and the original site, that attribution is required. By beginning the wiki with a referral to the original content, it is then inferred that all the following content is from this site, the quotation mark up demonstrating it is a copy and paste, with the link added at the beginning of the quotation for good measure to avoid any misunderstanding.

This example has original content followed by some quoted content. Here the copied content is clearly set apart from the original content using quotation mark up and it has a long link at the start of the quote to make it clear to readers where the quoted content is being sourced.

What do I do if I see a plagiarized tag wiki?

Use your best judgment.

If you can improve the tag wiki to comply with our guidelines, then do so! Suggest an edit that adds proper citations and formatting.

If the entire wiki consists of nothing but plagiarized content, and you feel it is not salvageable through edits (short of completely rewriting it), then flag a post (any post; it doesn't matter^*) for moderator attention and explain the problem with the tag wiki. Moderators can retroactively reject and/or roll back edits to tag wikis, and they can also reach out to users who suggest/approve plagiarized content.

_{* This is necessary because there's no way to flag a tag wiki directly. Flagging a post (either a question or an answer) is an acceptable workaround, as long as you use the "requires moderator attention" reason and type a detailed explanation into the provided textbox.}