Are you curious about the status of your friends in Yahoo Messenger or MSN???? Are they online, offline, or maybe invisible??? You don’t have to go online if you only want to check their status. Also you can see anyone who hide his/her appearance.
Go to this Link :
http://www.imvisible.info/
http://www.ydetector.com/
http://www.yahoo-status.com/
or if you want to see all from your list go to this page:
http://www.imvisible.info/check-my-list.php
http://www.quienteadmite.com/index-en.php
And here’s the status’ checkers:
http://www.checkmsnstatus.com/yahoo-status-checker.html
http://www.checkmsnstatus.com/msn-status-checker.html
the last two I gave are tools to see if someone offline in your list then. If he/she appear online in in status checker it means he/she has blocked you.
Now you know! 
hey … you forgot to put detectinvisible.com in your list.
And also http://www.statusdetect.com. Trust me…soon it will be the best
you didnt put http://www.invisibleyahoo.ro it has a hi5 detector too
Man, i use http://www.invizibili.com and it`s work very good.