The following two tricks lets you see who is invisibe in yahoo messenger.without his or her knowing that you are aware of his or her presence.This is a working trick.
Trick 1::::::::
..1..Open the conversation window of the person..whom you suspect to be online.
..2..click on IMvironments.find doodle from the imvironments.click on it
..3..you will see a screen..”Waiting for your buddy to load doodle”….Wait sometime
..4..After sometime if it is able to load….it means your so called buddy is online n he or she doesnot want to talk to you..
..5..if it doesnot load….you can be sure that he or she is really offline