As I defined in my post on gender, genderqueer individual refers to a gender variant person whose gender identity is neither male or female, is between or beyond genders, or in some combination of genders. Individuals that identity as genderqueer often challenge gender stereotypes and the gender binary system.
Genderqueer is a little different than gender fluid because it is the gender identity of not choosing one or the other, oftentimes ever. I like to think that the queer symbolizes queer as being a word referring to something out of the normal. This goes back to this idea of challenging the gender binary.
While I think gender fluidity is not being seen as much as sexual fluidity, gender queer seems to be becoming visible. MTV had its popular documentary show True Life follow genderqueer individuals, and it was pretty cool.