Tags can be done with typing and autocomplete...better?
We can change to this mode of UI in the Create New Post that I think makes the tag usage easier. There's help text under the window in this screen shot and it will contain instructions on the use of tagging, the benefits and also a link to a standing post to request new tags. I think this method of operation will allow us to add many more tags without making them burdensome to navigate.
Not quite sure how to connect groups to tags in this UI but that might be the next step.