In the last few days I've been hitting sites where this assinine
"social" toolbar called Meebo is at the bottom of my Firefox screen.

It only happens once in a while, not on every Web page I access.

Is it only certain sites that have this nonsense? I see in some forums
that some users are stuck with it on every page and can't figure out
how to get rid of it?

Did I get "infected" with this crap thing?

I read in one forum that Ad Block Plus can stop it. I do have Ad Block
Plus and did enter Meebo.com into it.

What is the story on this thing? No, I don't want to go to their page.
They might start shoving that crap of theirs down on me.