You can set invisible with yahoo messenger to tell that you are offlne but the real one is online  

But sometimes you need to know if your friends are just invisible or really not ..

I have tried many software and test by my account and realize the best way to do Yahoo Messenger Invisible Hack is using Buddy Spy ..

You can download the software from :http://www.buddy-spy.com/download

With this tool you can find any invisible friend ..

Here is how to use Buddy Spy :
After you install it, just click the shortcut to run the program
Than choose configure and fill the username and password of your yahoo messenger ( i prefer dummy ym so i won’t be log out automatically when using my real ym. Because Buddy Spy needs to login to yahoo account first )
After click login and succes in the buddy spy menu just fill yahoo messenger id which want to detect and click scan …
It will show the information if the id is online or offline
After i try it .. It show many succes detection than any other detector program ..

That the way you can hack yahoo messenger user which is invisible