Release Candidate of Writeup 2.0 includes a Mac verision
The release candidate for Writeup 2.0 has been released on sourceforge. See sourceforge.net/projects/writeup/files/ for the download page. New features kept creeping in and delaying the release, but this looks good.
The Drupal module for allowing Writeup to be an input filter is now stable. See drupal.org/project/writeup.