The Empress is a ruler, she's the ultimate feminine being, to some she's a goddess or The Goddess. She can represent Mother nature or just mothers and mothering in general.
She's the partner of The Emperor so she's regal and a leader too but her method of rule is caring, loving and nurturing.
She's about joy, abundance, creativity, sensuality. She experiences life with all of her senses, she's no shrinking violet.
When she turns up in readings she could be telling you that you need to be creative, put your heart and soul into something or just that you need to look after and nurture yourself or what every you're reading about.
She may also be advising you to take charge of a situation but in a caring or loving way.
And as Thirteen has said, she can be a bit overbearing or think that she knows best. She can be a bit smothering but it's because she cares so much
Her number is three so she's about growth, abundance, productivity and I suppose you could also get communication from that.
There are plenty of other cards that would make me think of communication but The Empress wouldn't really be one of them.
I'm sure others will come along with much more. Like all the Major cards, she's a complex lady.
Have you read Thirteen's page on The Empress?
http://www.aeclectic.net/tarot/learn/meanings/empress.shtml