Comments are a feature of blogs which allow readers to respond to posts. Typically readers simply provide their own thoughts regarding the content of the post, but users may also provide links to other resources, generate discussion, or simply compliment the author for a well-written post.

You can control and regulate comments by filters for language and content. Comments can be queued for approval before they are visible on the web site. This is useful in dealing with comment spam.

Reference http://codex.wordpress.org/Glossary