Good news, developers: Google is finally giving you the opportunity to formally submit a description of changes to your app in its latest version. Many devs were doing this in the description field already, but were constrained by the character limit in place. This new option frees up some space in the description for ... well, further description, and is sure to please some application developers out there. No sign of the ability to respond to user comments, though, sorry.

Source: Android Market Help via DroidReign