Chunks is about managing tiny bits of content on your WordPress site.
Chunks is for theme developers that have their themes filled with footer notes, copyright notices, block titles and descriptions, slogans, etc, which are sometimes hard-coded into the theme, sometimes localized (can be changed in po and mo files) and sometimes taken out to the theme options.
Chunks will do the job for you. A "chunk" is a piece of HTML code that could be inserted anywhere in your theme and edited from the Theme Chunks page under Appearance in your admin panel. Use register_chunks() in your functions.php to register chunks for your theme and use the chunk() to get the chunk value anywhere in your template files.
It'll take you 5 minutes to implement Chunks in your theme: Getting Started with Chunks