Is there any way to don't let user to create tags? Or to let it only to a group of users?
Not sure from permissions point of view, but I suppose it is not an easy task.
Some time I did some changes in Share relating this, for example, hiding the document library tag filter, hiding default content type metadata form, hiding inline tags from detailed view metadata template, hiding tag area in document details...
You can use DENY permissions in the category root for tags to disallow creation of tags for some users / groups, but the Share UI would not be able to handle that nicely (e.g. hide the functionality), always showing some kind of error / exception for that.
Yes, that's a good point.
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