You can login with multiple ID's on the same yahoo messenger. Follow these steps == Go to Start == Run == Type regedit,hit enter Go to HKEY_CURRENT_USER == Software == Yahoo == pager ==Test On the right pane == right-click and choose new Dword value . Rename it as Plural. Double click and assign a decimal value of 1. Now close registry and restart yahoo messenger. For signing in with new id open another messenger .