Tag sets in Stack Exchange are very useful, and I particularly like the wild card, however, I think it would be even more useful if it were possible to add an "except tag(s)" to the sets.
For example, *word* covers not only the Office product (msword, word-vba, word-2007) but also wordpress, so it would be good to be able to exclude a common tag that does not fit in with a wild card selection.