Sometimes some of your friends who appear offline in yahoo messenger may not be actually offline,they may in the 'Invisible' mode.This maybe if they are trying to ignore you or are too busy to talk to anyone. There is this small trick that you can use to find out what the truth is. http://www.mangmuaban.com let you find and check whois invisible,
Site Temporarily Unavailable We apologize for the inconvenience. Please contact the webmaster/ tech support immediately to have them rectify this. error id: "bad_httpd_conf" Another tool like this that detect invisible people on YM is www.imvisible.info and it works 100%