Posts are the entries that display in reverse chronological order on your home page. In contrast to pages, posts usually have comments fields beneath them and are included in your site’s RSS feed.
In the Comments Screen you can edit or delete content found in comments to your posts, and you can mark comments as spam, send comments to the trash, and reply to comments. A number of rules can be defined about who can write comments, and how comments are moderated. These rules are managed via Administration > Settings > Discussion.