Take this screen shot of the first page of tags on Stack Overflow:

First page of SO tags.

Take, for example, the tag there. The excerpt simply states:

[A database is] an organized collection of data.

Or even the tag, which states:

[Linux is] a Free (libre), Open Source, Unix-like operating system.

How exactly are these excerpts helpful? Anyone can think that up. It doesn't at all explain what that tag should be used for. The problem seems to expand through all tags. Excerpts have become a short summary of what the tag is, not what the tag is about. Oftentimes, excerpts are made to be just the first couple of sentences from the tag wiki itself.

According to the blog Improved Tagging:

  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 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.

Most excerpts I've seen only describe what the tag is, but doesn't actually give any guidance on when to use it, or how it's relevant to the community. Considering the tiny amount of text that actually gets displayed with the tag when typing it, these should be the first pieces of information present to make sure that our users are tagging these appropriately. While this may not be as big an issue for the larger tags on the first page, it's a consistent problem with smaller tags still starting off.

Robert Cartaino also explains this in not-so-many-words in A Note on Tag Wiki Excerpts.

Can we please work together to improve all these tag wiki excerpts to actually be more useful to users? For example:

The current wiki excerpt:

PHP is a widely-used, general-purpose server side scripting language that is especially suited for web development.

A better wiki excerpt:

For questions about syntax, functions, and other constructs of PHP, a server-side scripting language especially suited for web development.

Most notably removing the opinions of "widely used" and unnecessary statement "general-purpose" from the excerpt allows for more characters that can be used for more important and relevant information in the excerpt.


2 Answers 2


Have Stack Overflow's tag wiki excerpts veered away from their purpose? No. In many cases, it's not that the tag wiki contents have veered away from the purpose of the wiki, but that the actual purpose of the wiki has changed, and the tag wiki contents haven't adapted... or haven't needed to.

Once upon a time, the tag wiki excerpt was displayed on the question list for that tag. The excerpt was given a short but useful character limit, could include links, and would otherwise basically act as a simple landing page.

For a while, starting around when the blog post you cited was made, the excerpt was used for both the tag mouseover and the question list. That is no longer the case. Starting earlier this year, the excerpt is only used as part of the tag mouseover mechanism. The thing produced at the top of the question list for a tag is now a mechanically detached section from the full tag wiki and has nothing to do with the excerpt. This is very annoying when there's no full tag wiki to show on the question list.

I'm going to argue that the goals listed in the blog post are hard to apply to the current use of excerpts.

First things first: tags are for questions. Saying "For questions about..." is just noise and eats up the tiny character limit.

Some tags really do need a dictionary definition. Quick, what's ? If you said SpectateSwamp Desktop Search, you're wrong!

Not all tags need usage instructions. Those that do need usage instructions are the exception, really. I'd also argue that any tags that need usage instructions are probably doing something wrong, with the probable exception of version-specific tags.

Excerpts with marketing speak should be cleansed, but the dictionary definitions are fine when they add value to a non-obvious term. Remember, the primary use of the excerpt is now only in tag mouseovers. The character limit is probably best spent providing a "what" instead of just a "why."


From your example, I would prefer the current php wiki excerpt:

PHP is a widely-used, general-purpose server side scripting language that is especially suited for web development.

Over your suggested one:

For questions about syntax, functions, and other constructs of PHP, a server-side scripting language especially suited for web development.

Why? Because the current one tells me quickly, at a glance, what PHP is. True, I already know what PHP is, in this case, and most visitors here do. But maybe not everyone. And when there is a tag I'm not familiar with, then I want to tell immediately what it's for.

A more obscure example makes my point more clearly. I just selected the question that happened to be newest as I'm writing this: https://stackoverflow.com/q/11041554/13860

It is tagged with . As someone who has never heard of jenkins, the excerpt is immensely helpful:

Jenkins is an extensible continuous execution server...

That is the most important piece of information in the tag description. Obscuring that information with

For questions about configuration, syntax, and the API of Jenkins...

would reduce, not improve the value of the tag.

Second, "syntax, functions, and other constructs" is really a description of SO, more than of the tag. Asking about other aspects of PHP would be off topic for SO entirely. I wouldn't use a separate , or something, if I wanted to hear the story of PHP's invention. I would have to ask that somewhere else entirely.

  • 4
    I think it depends somewhat on the tag. Do you really need to be told what a database is? I think you'd probably rather hear which questions should have that tag. Ditto for C#, Java, JavaScript -- if you're a programmer and don't know what that stuff is, hang it up because you're utterly incompetent. But for more deeply specialized things, even within the programming field, I can see having some description of what the thing is. Still, that's not the focus. Commented Jun 15, 2012 at 5:01
  • @JeffAtwood: If English isn't your first language, you may need some of those terms explained. But that's probably even a stretch for the specific ones you mentioned.
    – Flimzy
    Commented Jun 15, 2012 at 5:08
  • 1
    If you need definitions of the tags on page one, the tags page of [whichever SE site] probably isn't the right place for you to be in the first place.
    – Pops
    Commented Jun 15, 2012 at 6:48
  • @JeffAtwood: Although I'm curious if you prefer the proposed alternative, which in my estimation, is simply a re-statement of SO's purpose. Or do you propose something else entirely?
    – Flimzy
    Commented Jun 15, 2012 at 16:48
  • 1
    @JeffAtwood -- It depends on the domain context: Most IT sites may not need a [database] tag, but many non-IT sites may well need to know the difference between a file and a database...
    – Martin F
    Commented Dec 23, 2013 at 20:41
  • 1
    If tag wiki excerpts have "veered away from their purpose" then their (original) purpose needs to be tampered. I've never thought that any explanations on "what questions should use this tag" have any benefit beyond mere filler. Definitions of the tag topic are far more useful!
    – Martin F
    Commented Dec 23, 2013 at 20:50

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