Growl, the hugely popular notifications app for Mac OS X, is preparing itself for OS X Lion and is migrating to the Mac App Store. The application is to be completely revamped in both code and design.
Previously, you could only download Growl from their site but by moving into the Mac App Store they are aligning themselves to a common source of apps for Mac and will use the MAS to distribute their frequent updates.
Growl is a notifications app that monitors activity in other apps and alerts when something has occurred. Many apps recommend you to install Growl in order to be notified of things that require your attention. Apps like Dropbox, MailPlane, and Adium all use Growl for notifications.
Growl is probably in the top 10 most popular Mac apps based solely on its tie in with with other apps for notifications. A revamp and Lion-centric approach is welcome news.