I've been updating this site since last month. One of the things I added is able to serve gzip-encoded page. On top of that, my site is also able to serve gzip-encoded CSS and JS file

Just scroll to the bottom of every page and you'll notice a line that says something like
"Gzip enabled , CSS compressed , JS compressed". This will give an indication whether they are enabled or not. In other words, this will make pages load faster as well as saving some tiny bandwidth.
I've written a how-to thing that gives you an idea how to achieve that with PHP using
ob_gzhandler(). For this to work you'll need the appropriate version of PHP, zlib extension and web browser that supports compressed web page.
Link:
[PHP] How to enable Gzip compression on output buffer
Next topic will be on how to shrink, compress and cache CSS/JS files. Those who're using heavy AJAX and CSS styling will benefit from this.