First of all,G00d Day..

You decide whether you want friends to know if you’re not using your computer. To reveal o r conceal your Idle status:

Click the Messenger menu in Yahoo! Messenger and select Preferences.

Click the "Privacy" category.

Locate the "Idle Status" se ction.

Choose whether you want to be shown as "Idle" after a period of time or never be shown as "Idle."

Click ‘OK’ when done.

Be Happy ,Güd Lück