They normally have some sort of fella with a megaphone orchestrating what to sing and when to jump. It may be impressive, but it is not organic. I think the English crowds are more about actually watching the games, reacting when appropriate, rather than being part of a giant sing-a-long and...
The was my experience from wsu, I could see AEK jumping up and down, but mostly all I could hear was us.
I record the games and if we win I watch them back and I am always surprised how much quieter it is on tv then it is live.