Is this still the most up to date reference for creating a custom tagging system?
Should it be possible to add the same linked element more than once to a page?
e.g. using the method described in the link above, when you are on the document ad adding multiple tags to your document, it lets you add the same tag more than 1 time. This doesn't really make sense, as why would you want a linked document (tag, category etc) added more than once?