This is a space, easily accessible from the front page, where you can practice your LaTeX/MimeTeX commands for writing equations for adding to discussions, etc. You can see several people’s experiments at the earlier post here.
The key thing for getting your equation to show up on the site in a comment is to enclose it between the following two delimiters:
[ tex] (LaTeX-like commands go here) [ /tex]
…but don’t include the spaces after the brackets. I had to do that just now to stop the blog machine from turning them into instructions to make an equation.
Beware that for some more technical things (such as pictures) the mimeTeX command set is a bit different from the LaTeX ones you might be familiar with. Consult the manual above.
From time to time I will come in here and clean up the mess, so don’t leave things here that you want to keep for too long. This is just for practice.