You want to chat with a buddy on Yahoo! Messenger but his status on Yahoo! says Off-Line. There are two possibilities here - your friend could be really offline or he may have logged into Yahoo! Messenger in “Invisible Mode” to avoid interruptions. (Yahoo! Messenger has a Stealth settings feature that lets you choose the people who see you as online and offline.)
You can however beat that mask easily with services like Xeeber or VNGrabber that reveal the exact status of your Yahoo! Messenger friends. All you have to do is type the Yahoo! Messenger username and you will instantly know the exact online status of that person. Time to put on your detective gloves.