I have a suggest: It is preferable that when adding a tag, a drop down list appears showing the related tags based on my existing tags. This will ensure not repeating tags or duplicating them due to different spelling or one is capitalized and the other is not.
For example, when I tag notes from the quotes of the father of the church I found many tags: Patristic, Patrology… Better they have same tag to be linked together and easy when searching.
