By default, Adium only provides five status message for you, i.e. Available, iTunes, Away, Invisible, and Offline. If you want, you can easily create new status message which will inhabit your Adium status message selection for eternal.

Here is how to set your new status message :

1. Launch Adium
2. Expand your status message or you can also click the Duck face on your menu bar
   

   

3. Click on Custom and you will be directed to Custom Status Pane
4. Type your new status message on your title
5. Tick the Save Custom Status checkbox so that you status message won't be deleted even though you relaunch your Adium
   

   

6. You can also set auto-reply message which is quite obvious