growl is a unified notification system for OS X. While that doesn’t sound like much, it’s a transformative UI experience to have all of your apps notify you through the same customizable interface. After installing it, I immediately wanted to look around and find other things I could route through it.
There’s also a command line tool that lets you send notifications to growl from scripts. I wrote a cron job to do time notifications:
0,15,30,45 * * * * /bin/date +\%m/\%d/\%y\%n\%H:\%M:\%S | /usr/local/bin/growlnotify -n BEEP -I /Applications/Countdown.app
I set the “BEEP” application in growl to use the bezel style, and I get a flash every 15 minutes in the middle of the screen to remind me that time is passing. (I used the icon from countdown because it was the only application I had with a clock.)
I really can’t express how useful this is. I’ve never been quite happy with how any of the IM programs I’ve used have handled notifications, but Adium integrates deeply with growl and has allowed me to set things up exactly as I want, so that I see the important things, but I don’t get cluttered up with having to click on every little notification to make them all go away.
This is very very good.