What is "urban" art?

Phillips de Pury, a major art auction house, recently held a sale of "urban" art. Flavorwire did a nice interview to help explain "the rise and relevance of this movement." Art consultant Ken Miller says:

To me, “urban” art is kind of a misnomer at this point. I think youth art might be more accurate, since it speaks to a youthful pop sensibility and a range of influences from youth culture. This includes graffiti and street art, but also punk rock, graphic design, advertising and more.

Auction curator Alex Smith defines "urban" art:

Graffiti is as old as time and could be defined as unsolicited expression and a type of urban folk art or vandalism found mainly in public areas. It’s typically made by unseen, youthful forces. Graffiti is urban but urban is not graffiti. Urban [art] has quickly become the umbrella term for anything with even the loosest ties to and origins with graffiti and street art. I think the corporations (and perhaps the auction houses) are the easiest ones to blame for this. It’s a convenient blanket term that has become frequently misused of a certain graphic style, and as a byproduct [the term] has been stigmatized by the many of the artists associated with it.

Interesting! More here.