I love discovering simple tricks that WordPress allows you to do simply with the URL. For example, adding ?=random to the end of a WP blog will produce a random post.
Chris Aldrich’s provides another:
So in general, for WordPress sites one can append ?link_cat=[category id] (with or with out the brackets) to the main URL for the OPML file typically found at http://www.example.com/wp-links-opml.php.
When we talk about coding it small tricks like this which excite me because it feels as if they touch on the way that the web works, as much as the outcome at hand.