The My Thesaurus plugin enhances note organization in Obsidian by automatically tagging notes based on a custom thesaurus. It scans note titles, properties, and content for predefined terms and their synonyms, adding corresponding tags without requiring manual input. The plugin supports both CSV and Markdown-based thesaurus formats, allowing users to define custom term-synonym mappings. Users can configure search sensitivity, including case-insensitivity and optional accent removal, ensuring flexibility in recognizing variations of words.