Why would you ever have empty blockquotes?
http://en.wikipedia.org/wiki/Smith_%26_Dale#.22Dr._Kronkheit_and_His_Only_Living_Patient.22https://en.wikipedia.org/wiki/Smith_%26_Dale#.22Dr._Kronkheit_and_His_Only_Living_Patient.22
SMITH: Doctor, it hurts when I do this.
DALE: Don't do that.
SMITH: Doctor, it hurts when I do this.
DALE: Don't do that.