As I am using linux, I wrote a libnotify support instead of growl notification
I changed the notify structure so everybody can add new notification system.
Add libnotify gem dependency
Add notification with libnotify with --libnotify option
This sounds like a great addition! I'll take a look tonight.
Sorry I didn't get around to this yet. I think it underlies some things I wanted to investigate for notifications in general. Mountain Lion's UserNotificationCenter should be supported, and Growl support should be more comprehensive with clickbacks. Doing something on Windows would be cool, also. This is getting high on my TODO list, will keep you posted.