List of predefined labels or tags that are only allowed to end-users

Currently the users may add tags to comments in entirely free way without to respect any convention. This limits the reusability and makes almost useless these user-defined tags as one difference in a character/symbol makes them separate items. It would be much better and useful to have opportunity to predefine a list of possible tags (or labels), which to be then only offered to reviewers, e.g. on same way as the labels in some mailboxes work. So, we can for instance predefine a list of labels that fit to the MoSCoW prioritization - and when there are some comments to ARIS content, the users may easy reuse these tags/labels and say for a comment that it is a must-have, should-have etc. And at the end, using this tag we may easy sort all the comments that should be implemented.