If you are from US or your Live Id's country setting configured as US, you will notice that something is seriously wrong on the Windows Phone store (marketplace) about ranking: The display order of "Top" apps in all categories (except the "All" one) seem reversed on this morning. Please have a look at the photos I just took:
This problem apply to the web market as well:
As you could see, most of the "top" apps do not have or have very few review and rating. I hope Microsoft could resolve this as soon as possible. Yesterday my IP CAM Controller was ranking at the top 11 position in the "Music + Video" category.