Readers of an article on your site usually look for other articles on the same topic. Categories and tags are a way of showing them related articles. Elegant displays the count of articles that you have written in a category or tag in a non-intrusive manner.
Every category and tag has the count of articles in superscript. So if you have written three articles in the C++ category or tag, it will have 3 in the superscript. This way visitor will know you have written other articles too on the same topic.
Check out the screenshots,