Growl, perhaps the most well-known and popular notification system for OS X, has just released version 1.3 as a Mac App Store exclusive. The previously free notification system has become a paid app with Growl 1.3. As Macstories points out, the reason the Growl team decided to make what was previously a free System Preferences pane into a US$1.99 app was so users would be provided with an up-to-date app ut
