Tags are not added to profiles, I believe what you are wanting is a category.
Looking a the space page created, you added [[Category:David Simms]] which is showing in red (because it does not exist).
As a note, the category you are trying to create should not be created in this format. Most categories are global usage and this type of category does not neatly fit into the approved hierarchy.
What you should be looking at is a Personal Category. I have gone ahead and changed your category on your project page. You can add profiles to it by using the following:
[[Category:Altenburg-72 David Simms]]