A recent question came up using the colors tag. Right now, there are only 10 questions with this tag, and they mostly seem to refer either to faces or font-lock.
The colors tag seems ripe for retirement given the small number of tagged questions and ambiguous use. Would people prefer to
faces or font-lock (and if so, which?), or 
git diff --color) but it's a symptom, not the root cause.Conclusion: 4/10 definite misuse of colors instead of [tags:text-properties], [tags:faces] or [tags:font-lock]. 4/10 where colors is marginal. 2/10 where colors is important, including one where it's legitimately the sole tag.
I don't think we can get rid of colors, though we should discourage its use when the question is really about text-properties, faces, font-lock or themes.
I propose to keep the tag, and write a tag wiki that explains when to use other tags instead. (I'm putting it on my to-do list; if someone wants to do it, they're welcome.) I think we can live with that, and retag mistagged questions as they come in. Let's see how it goes, if we're overwhelmed by misuse we can consider retagging legitimate uses to color-something with a name that discourages misuse.
faces (even though it's not a good tag here). Generally I would be fine with letting a tag exist because there's one question that really needs it. But this tag in particular is doing more harm than good. It's fragmenting questions about all these other tags, and mixing them up in one meaningless tag.
IMO, synonym would be better as everyone might not be familiar with the emacs terms like faces and font-lock.
font-lock as it means locking color/size/shape/etc properties to a font to give that text some special meaning.
Commented
Feb 13, 2015 at 19:41
colors, by itself, is much closer to faces than to font locking IMO.
There is zero reason to remove tag colors. There is every reason to write a tag wiki that specifies what the tag involves.
More precisely, I would propose changing the tag from colors to color. The confusions that some of you are worried about will, I think, be reduced just by making this name change.
It is questions about color (color models, how Emacs Lisp manipulates colors, etc.) that should be captured by the tag, and not questions about faces, themes, font-lock or other highlighting, etc. (they have their own tags). IOW, the tag has a raison d'etre, and that is questions & information that are specifically about color (not colors).
And no, it is not the case that (as Malabarba said) "A color, in elisp, is nothing but a face attribute." Faces might be where Emacs Lisp uses color, but questions about color do not necessarily reduce to questions about faces.
There is plenty in Emacs that is about color and not just about faces, themes, font-locking, etc. And even some posts that might have to do primarily with faces or themes etc. can also involve specific information about color.
It is not because some questions about font-locking or whatever do NOT involve dealing with color issues specifically that there are not other questions that do deal with color issues (as well as with faces or whatever).
It is not an accident that Emacs has functions for manipulating and displaying color names and color RGB or HSV components.
The proposal to replace (merge) tag colors with faces or any of the other tags discussed is misguided, IMO. Rename it to color, and clarify to users what the tag is for. The tag wiki can specifically mention other tags such as faces and when to use them.
Yes, merge it into faces and make it a synonym. Other tags like font-lock or text properties might be worth adding to some of these questions, but they have more distinct meanings and that's a case by case thing. The tag color as a whole should be a synonym of faces.
Out of all current uses, the only one where color suits better than faces is: Are there color pickers for Emacs? . And even here faces would be an acceptable tag (though we can manually find a more appropriate one for this).
As a second point, what would be the purpose of a color tag? A color, in elisp, is nothing but a face attribute. Having a color tag is like having a weight tag or an underline tag. It's too small to warrant a tag (as exemplified by the total of 1 use so far where it works better than faces).
color property of faces, so I disagree with your statement. Of the 10 questions, 8 of them can easily be tagged faces. Of course, most of them can also be given other tags (and they should, that's what I said on the first paragraph).