What does it mean to be a brony?

There is a difference between being a Fan and being a brony(or pegasister). A Fan just watches the Zeigen and enjoys it, and that's fine. A brony is touched Von the Zeigen on another level, and therefore, joins the brony community. When you're a brony, friendship truly is magic. Du help your Friends when they're in need, and stand up against those who try to put Du down. Du can have fun talking about MLP:FIM, Schreiben fanfics, drawing pictures, RPing, and so much more.
That's what being a brony means to me. :)

Basically what DragonAura said.
Bronies/Pegasisters are really in touch with the show, as they know a ton about MLP and make a bunch of fanart of all sorts, like drawings, music, and fanfics. They talk about it on both internet and real life. Go to conventions like Bronycon and Everfree. Besides, it's not just those. It's believing the true meaning of friendship and happiness. Making Friends near oder far.