Tags come in (essentially) three colors... and these three colors are limited to meta sites only.
- Mod tags - red/maroon.
- Required tags - grey.
- General tags - white or nearly white depending on the site.
As far as I know, all tags on a main site are the same color with the exception of the custom sponsored tags that some sites have, which have fun icons of the brand on them, like the Android tag on SO.
Some sites (not many, but some) have very specific types of tags. For example, on Movies & TV, we have tags for film titles, Sci-Fi and Fantasy has tags for titles, authors, etc… Anime & Manga is similar.
Occasionally, on M&TV, we get users (usually 1 rep) who use generic-looking tags like aliens to ask questions about… well… aliens in films… but the Aliens tag, as the tag wiki notes, is for questions about the film Aliens. Sometimes, if these tags are for less-well-known films or were recently added, they don't have excerpts at all… this, obviously, is a separate issue.
To add to the title specific uses above, this request was recently made here on Meta.SE:
Some SE sites have questions that apply only to certain countries, or where answers should at least take laws or customs in the country in question into account. Example SE sites would be Workplace, Academia, Expats, Travel, Money or Law. These sites use country tags for this purpose.
Changing the color of the group of tags would be a less intrusive solution to the request to add tiny flags to identify country tags (and it would be less work). The tags already have the country name on them, so all that is needed to set them apart visibly is a different color of tag (one color for all country tags, not one color per country). This would make all of the country tags on a site more visible while not interfering or watering down Stack Exchange's ability to sell the icons to interested parties.
What I would like to propose is a specialized type of tag denoted with a different color that allows sites to do a couple of things:
- Makes it obvious that the tag is not for general use, particularly when the tag looks like it's generic (see the aliens example above).
- Makes the tag stand out on a question as a form of classification.
- As on Meta, these tags would have precedence over other tags and be listed first to make them more obvious.
- As with the tags on meta, they would not be exempt from the five tag limit.
- Potentially, this could allow a site to have more than one tag with the same name but that's not completely necessary. This could have its own set of problems but it might be something that could be worked around and help out a lot when you have issues where a book or film title or a brand is the same as a common subject matter. This is something I think can be discussed separately rather than being a part of the initial implementation.
There are certainly other benefits that I'm missing above.
To help implement these tags correctly, I recommend that the creation/reclassification of new tags should be initially limited to either mods or sufficiently high-rep users (10K+). For established sites, this will be quite an endeavor at the outset as there are likely hundreds of tags that will need to be classified.
As one would expect, this is something that should be implemented on a per-site basis and be something that the site has to show a particular need for and community support of before it is allowed.
As a note, on M&TV we have recommended a plan to set film and TV tags apart by including the year of first release in the tag but this plan is on hold due to the issue with film/show title length often conflicting with the 25-character limit for tags.
Note, I am not asking to Allow custom colorization of tags, which relates to a user-setting to mark favorite tags.