I discover how to build LaTeX code in the editor and view the resulting file in a PDF viewer on Mac.
Local texmf directory on Mac (Snow Leopard)
I find out how to set my local texmf/ directory on Mac OS.
Chemical structures
I work out how to draw chemical structures in LaTeX.
LaTeX
I decide to keep a record of how to do things in LaTeX in the hope that it will help me and others.