Here's something we've noticed over the last few days and was brought to our attention by some developers: basically no new ratings/stars are being calculated. If you have 200 ratings before a few days ago, they're essentially frozen there. If you're a new app or game introduced in the last few days, you may be getting reviews from users, but the star-rating and counter are not being updated to reflect new reviews.
Many users, including ourselves, use the star ratings (and review count) to get a first impression of an app. You see a game with 4.5 stars with 50 reviews, well, you know that's a game to download. Vice versa, if a game has 2 stars and 121 reviews, you know to avoid it. In other words, these ratings and their accurate reflection are key to an app's success in many ways.
Case in point: Jet Car Stunts, released this past Wednesday, has plenty of 4 and 5 star reviews but the overall rating for it? No stars, zero reviews.
We hope Microsoft is aware of this problem and working to get it fixed. But hey, it may not hurt to bring this story to their attention.
Thanks, Daniel J., for reminding us about this