Microsoft enabled Windows Phone developers to respond to app reviews in April. Since then, developers have been using the tool to reach out to their users and improve their apps. In addition to better apps, users get to resolve issues they are having with their apps. This is a win-win, because happy customers and happy developers improve Windows Phone's reputation.
According to Microsoft, 20% of Windows Phone developers have responded to at least one customer review. After the customer has been contacted, 10.5% of them update their review. This review update on average increases the score of the app by 1.2 stars.
This feedback loop great for developers who have a limited number of devices to test their apps. Now customers who have difficult to find bugs can help the developer make their app work flawlessly on all devices, even though they don't personally own the particular device. Feedback also benefits users who may be using the apps in unique scenarios such as low service or in a limited device access capacity (kids corner, no SIM, etc). Developers can now get more information and help their customers use their apps to the best of their ability.
in response to this success Microsoft has updated the guidelines for responding to reviews. Developers still should not market or promote via this service. More specifically developers should keep responses relevant to the app issue the customers is having. If a lot of customers are having the exact same issue, then it is okay to send the same response to those affected. Developers should not lump responses to customers' problems together if they are not similar. Finally developers should not attempt to manipulate their app's ratings via review response.