Sometimes some of your friends who appear offline in yahoo messenger
may not be actually offline,they may in the 'Invisible' mode.This maybe
if they are trying to ignore you or are too busy to talk to anyone.
There is this small trick that you can use to find out what the truth is.
Firstly
open your yahoo messenger main window and double click on the name of
the person whom you want to check.The chat window will open obviously.
Click IMVironment button, select See all IMVironments, select Yahoo! Tools or Interactive Fun, and click on Doodle. After loading the Doodle imvironment there can be two possibilities
1.If
the user is offline Doodle are will show this "waiting for your friend
to load Doodle" continuously .See in the picture below
2. If the
user is online (but in invisible mode), after few seconds {It can take
up to one minute, depending on your connection speed}, you should get a
blank page like in the picture below.So you know that the user is
online.