You can check if youryahoobuddy is invisible to you or not. Just install and activate this small useful plugin

click to go to download page

the plugin will be unzipped in your c:/programfiles/yahoo/ messenger/plugins/Please unzip in different directory if youryahoomessenger’s installation directory is different, but it works in most of the cases. You can activate it by clicking “action” and then “load test plugin” in youryahoomessenger’s main window.