What determines the tags (if any) listed in the page title?

Question

While reviewing two of my questions I noticed the following:

1. Penalty-enhanced approach to float placement
   • 1 answer, accepted
   • Tagged floats latex-project)
   • Page title: latex project - Penalty-enhanced approach to float placement - TeX - LaTeX Stack Exchange
2. Penalty-enhanced approach to float placement in LaTeX3
   • 1 answer, accepted
   • Tagged floats latex3 latex-project)
   • Page title: Penalty-enhanced approach to float placement in LaTeX3 - TeX - LaTeX Stack Exchange

Despite being very similar questions and having very similar tags, the first has a tag listed in the page title, while the second does not. Furthermore, the tag that is listed is not the first tag on the question.

My first theory was that the second question had a longer title and the tag was not included to satisfy some target length for the page title. But I've found shorter question titles that did not have a tag in the page title (natbib package error) and longer question titles that did have a tag in the page title (Can I install TeXLive on Windows 7 just by copy/paste (without affecting the system/registry)?).

What determines the tags (if any) listed in the page title? Is there some rhyme or reason behind this decision that I've missed?

Answer 1

First of all, when you tag a post, the list of tags at the bottom of the post is displayed in order of popularity (most-used to least-used). Hovering over the tags under the post will show the number of questions tagged as such:

So, discussion is more popular than tagging, which in turn is more popular than user-interface.

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Stack Exchange learned that it would be good to include tags as part of the post title when displayed in a browser as it improves SEO. That's the reason why they're in there in the first place.

Which ones are used? The most popular unless that is already included in the title. Moreover, only the first two tags are considered popular enough for inclusion. Based on your examples,

• Penalty-enhanced approach to float placement already has the word/tag float in the title, so latex-project is used;

  

• Penalty-enhanced approach to float placement in LaTeX3 already has the words/tags float and latex3 included in the title, so no further "optimizing" is required

  

The above guidelines take pluralization into consideration. For example, a title with "float" is considered similar to a title containing "floats".

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The question now could be asked whether or not one should include tags in your title or not, since they're included anyway (to some extent). Read up on the FAQ: Should questions include “tags” in their titles?

_{It's really useless to include the tag explicitly in the form "Tag: Title" or "Title in Tag", since tags (should) provide the relevant context.}