Anonymous
Favorite Answer
If you blocked a person on Yahoo! messenger,you have to right click on his name and appear off-line to him,you can choose also to appear permenantly off-line to him,he won't see you on-line,but you can still send him IMs and receive IMs from him,To ignore him,then you have first to delete his name from your list,then add him to your ignore list,by this way you won't receive any IMs from him anymore.
If you blocked him on MSN,then deleted him he will be able to know that you deleted him by going to: tools > Options > Privacy > View who added you,he will find your name is absent.so,he will know that you deleted him from your list.
On Yahoo,he won't know that you deleted him,he will also find you always off-line.
Anonymous
no once they are blocked they cant see you and even if you re-add them they will still show up on your yahoo or msn as blocked
Anonymous
If they still have your address then yes they will see when you are on line.
the only way they can't tell is if you keep them in your address
book and perminantly block them.
good luck.
c yah..