Shoutbox

hello i registered just to ask this one question that puzzles me 
i had a strange situation and i cant figure it out i need expert help i will react the event and hear your thoughts

i was connected to messenger as "appear offline"
i opened a window with this girl she was blocked i block her
opened the window to see her display pic! i do it all the time.
so the pic did not load for few days now so i unblocked her and opened a window
and i am  "appear offline" then when the window is opened i get a message from her and i am "appear offline" how did see know??? how did she write me??

i searched the matter and installed this discovery thing
it shows if someone opens a window with me
then i asked a friend to go "appear offline" and open a window with me several times when i am online   and i got NO message

then i asked him to be online but block me and then open a window with me  several times again NO message

got a message only when a online user opened a window with me

how..how?? how did see write to me? what happened there i still cant figure it out i am sure its got to do with me unblocking her but i was still "appear offline" very scary.

expert thoughts time now.  GO!