Hi Warren
Finding resources or people that a user has interest in is what workspaces are aimed at providing . You can see examples of this in the community site in The your space menu.
You can search for workspaces or resources of interest using the Catalog under the Explore menu and join a workspace with common interests for discussion and sharing of resources.
If you are still wanting to use interest tags these are added to the default collection and clicking on a tag in interests on your profile
will show other users with the same interest tag
There aren't any reports that include the interest tag. There is a tag block that could be added to a dashboard or home page that displays tags used and when clicked on directs to the same page as above.
Regards