It has been a long time since I wrote any articles. Now that I have a little more time on my hands, I will probably be adding more. The last two articles were XHTML-specific, but my new one on preventing “hotlinking” is Apache-specific, because it relies on .htaccess.
There are two basic methods in the article. One involves substituting requested images for an alternative. The other is a simple denial (serving up an error). There are a number of variations to play with, and the techniques can easily be adapted to work with files other than images.