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This plugin allows you to dynamically return the number of posts in a particular category, tag, or custom taxonomy. Inserting [cat_count value="category-slug"] in a post or page, or <?php do_shortcode('cat_count slug="category-slug" '); ?> anywhere in WordPress' code will return the number of posts in that particular category.

Useful for creating dynamic table of contents pages, keeping track of post stats, general bragging, or any place where keeping a running tally might be desirable.