I'd be curious to know how you use the service. Most of the questions I see asked on it seem pretty poor and uninformative.
An example of a question (and an awesome answer) I submitted: http://vark.com/t/cad4a0
Like many social networking features, I don't get this one. I sorta-know what my friends know - I am more interested in stuff my friends don't know.
I've also never actually gotten a question from a friend.