Question about facebook chat?

[Lilybeth]

Hi, I have several questions about the chatbox in facebook.
First, OL friends have green dot right?
so what are friends that appear in the chat box that doesnt have any dot(green or gray) ? are they offline?
Second, why is it that not all my friends are shown in my chatbox?
Third, what does it look like when I block my friends to see me OL when Im OL ? What is shown in their chat box?
thanks.

[Geo]

Yes, online ones have green dots.
Not all friends are shown because there are too many.
If you block, your friends see you offline.

Go to the help section in facebook for more details.