The Smart Links plugin for Obsidian allows users to create customizable auto-links within their documents. By defining replacement rules in the settings, users can set specific patterns to be transformed into clickable links while in reading mode. This feature is particularly useful for users familiar with platforms like GitHub or Phabricator, enabling seamless integration of familiar linking conventions. The plugin provides a flexible interface to configure regular expressions and replacement strings, catering to both simple and complex use cases. It enhances document navigation by linking patterns like issue numbers, financial symbols, or custom tags to corresponding URLs.