The layered navigation module is now only about features.But it should be rather easy to extend to to attributes and tags.
With attributes you could solve the classic fashion store question: “I want to see all clothes for which size XXL is available”.
Tags are suitable for have/have-not questions. Typically only the “have” part is interesting. On a clothing store you might use to enable the visitor to select only leather clothes. But you don’t want a separate option not-leather as you don’t expect anyone interested in that.