A few days ago we reported that it appears developers will soon be able to make their responses to reviews public.
Now Aggiornamenti Lumia reports that the feature is now available, meaning that if a developer for example has a critical review due to user error they will be able to make a constructive response not just to the user, but to anyone else who happens to read the review.
Hopefully we wont end up having knock down battles in the app store, but look out for this element coming soon to the review sections there.