Snippets offer functionality similar to standard PHP-execution filter, but I hope in more flexible manner. Site admin or power users may create named snippets of PHP-code (with access to Drupal API), then categorize and store them to the site code repository. Particular users can't view PHP-code - only snippet name and help. From user point of view - snippets are macros, which may be used in postings - nodes and comments. Macros may accept parameters which transferred to snippet code. Example: [macro], [macro|param1|param2], [link|9165]. You may imitate many filters such way, instead of separated modules for each small filter and allow users to create dynamic pages.
Now module offered this functionality in alpha stage (usable but some features not released yet). You may get it here www.drupal.org/node/17571. I'm very interested for user response. In future I plan to use this module in wiki engine and interested in its usability.
Example screenshots of the snippets (interface in Russian):
* www.drupal.ru/files/snippet-nodelink.png - created snipped, worked together with codefilter module, which used for syntax colorize
* www.drupal.ru/files/snippet-repository.png - fragment of the page with repository of snippets
