I found trick for make annoying to your friends in your Messenger list. Just for fun only ! If not there's a risk to you getting remove from your friends Messenger lists :)

Yahoo Messenger Online Offline Annoyner

This is really fun, I do this just only one time , Because if not I know definitely my friends remove me from their messenger list. But if we do this with our enemy, There is something to talk.It's up to you. I write this tutorial because of your knowing just how to do this.

First you want to download a file from here
> Download

It is a zip file,
  • Extract it to your desktop or any other place in your computer just as normally you do for a zip.
  • Then connect to the internet and open your yahoo messenger.
  • Login to your account just as you're doing every day.
  • Double click on Yahoo Online Offline Annoyer.exe to open
  • Now go to Contact > Add contact > and type your Id in that Box given in the ADD TO MESSENGER LIST window ( We doing this for experiment purpose )
  • Now Click the button of Start Annoying In our small programme.
  • Then see what happen ( If yahoo messenger gives a message about invisible situation just un check the small box appears in the left side corner in that window. )
Note: Just do this with your friends only for fun if not you will get remove from everyone's messenger lists.