You can if you use personalized status (f.e to let them know where you are etc.). When you put your status to away you can set it in the screen you get
Edit: yw
Another feature you might find handy:
The come-back message (rightclick contact > plus extras > set come-back message..don't forget to check that lil checkbox on top left to set it). If a contact goes offline and you leave your comp (staying signed in) and you wanted to say something to that specific contact, you can put that in the come-back message. If that person signs in again he/she will get that message automaticly (providing you are still logged in)