Chat disappeared ;-( Help please.

Hey all~
So you know how there is a chat thing on the bottom of the screen that shows what friends are online and you can chat to them? Mine disappeared, and it isnt just hidden. I cant see any friends online, or even the icon. Is anyone else having this problem, or is it just me? Anyone know how to fix this? Thanks so much!!!

Linds

On my screen there is a teensy little curved tab with two arrows pointing down.  If I click on that it opens up the line.  If you don't have that, I'm sorry I don't know how to help.