In many places in the documentation, when referring to the original ggplot library, the URL http://had.co.nz/ggplot/ is given for a link. However, this URL seems to be obsolete, I get a 404 error. The new website seems to be http://ggplot2.org/. Maybe it would be a good idea to change the mpl docs accordingly.

Is there some macro defined somewhere, or do we need to grep on the whole source tree?