Bookmark dumping ground:

• Xyzzy News' IntroComp 2003, a contest to write the beginning of a new work of interactive fiction. And only the beginning.
• inform-mode for Emacs, a major mode to write Inform interactive fiction story files.
• Xeena, IBM's Java-based visual XML editor.
• Buzz outliner, for many platforms, uses OPML. Written in Python. See Buzz's source code in OPML, displayed with XSLT and JavaScript.
• Arboretum, outliner for Mac OS X. "April 04, 2002: Still out here. Round tuits in short supply."
• Woody, another outliner written in Python.
• Of course, Radio is an outliner. Taming the Radio Outliner.
• Loading OPML documents using server-side XML parsing. Nifty source viewer, too.
• Welcome to NeoPets!