[OS X TeX] LaTeX based journal

[Sam]

You could use Wordpress (wordpress.com) with the latex plugin:
http://wordpress.com/blog/2007/02/17/math-for-the-masses/

I have my research blog set up behind an .htaccess password-protected
directory on my website, which provides enough security.  You could
also run wordpress on your Mac if you don't have your own website.
Here's an old tutorial:
http://maczealots.com/tutorials/wordpress/

Hope this helps,
~Sam