have a feature that lets you add a tag to mutiple resources.
That way if you forgot to add the tag "debate" to a lot of your sites, you can add it to all or some of them!
Ivan Tishchenko commented
Looks like it is already supported. Open My Library on the site, switch to "Advanced" mode (it's under "View" combobox, on the top right). After this, you can check the items you want to update (using checkboxes on the left of each item in the list), and in "More actions" choose "revise tags". It will allow you to add tags to all the items you checked.
Removing my vote from this item.