If you look at the posts about tagging you can see that several of the recent discussions where concerned with tags that some user created and somebody else questioned the usefulness of the tag. In some such discussions, the consensus was that tag should be removed - but in the meantime the tag was added to non-negligible number of questions, which means that those questions were bumped unnecessarily.
I had a look what can a user creating a new tag find from FAQ/help. When somebody attempts to create new tag, they are shown a warning, but it contains basically only the question "Are you sure you want to create a new tag?"
In the help center there is this text:
Most common tags already exist on a mature site. You should always favor existing tags; only create new tags when you feel you can make a strong case that your question does cover a new topic that nobody else has asked about before on this site.
The network-wide FAQ on this is here: When should I create a new tag? How do I request a new tag if I don't have enough rep? It mentions the stuff similar as in help center, slightly in a more detail. Here is one part mentioned there.
If you think there is a clear need for a tag, go ahead and create it yourself. If the new tag causes controversy, you can always come back to your site's meta to ask the community to judge it.
The current revision of the tag-info for tagging does not contain any information about creating new tags.1,2
I would like to ask:
- Is the text in the help center common for all sites, or can it be customized on for each site? If we can modify it, is there something that should be added there?
- Should we create a separate post on meta dealing with guidelines for tag-creation? And if we want to create something like that, do we have enough stuff to be mentioned there - beyond the warning that one should be careful about creating new tags?
- If we do not want a separate post about this, would at least mentioning something in the tag-info be a reasonable thing to do?
There have been several discussions here on meta where the focus of the question was when a new tag should be created (or some related issues). Some users even say that they would prefer if most (or all) tags were discussed on meta first - but I do not think that there is a real consensus about this.
But still, we could mention at least some stuff which is uncontroversial, such as: "When in doubt about the need for a new tag, you should discuss the creation of this tag on meta first. Do not retag too many questions soon after creating the tag - leave a bit of time for others to notice the tag and to raise their objections on meta if they do not find the new tag useful."
1I think that tag-wikis on meta are good places for collecting basic information on some topic. If somebody wants to point another user to a useful information about something, they can simply link to the tag-info. And this has the advantage that the comments containing this link do not get outdated - when some of the information needs to be updated, this can be done in single place, namely in the tag-info.
2On Meta Stack Exchange there is also the tag-creation tag. I think having such tag on our local meta would probably be too specific, it is enough to use tagging for topics related to this. (Moreover, the tags were used in this way for a long time, so probably this would be too big change.) But it sill might be worth mentioning that the tag-info for tag-creation contains a few other related links - in case somebody wants to read more about tags or simply check what already exists in the network-wide FAQ.