Excerpts are optional hand-crafted summaries of your content. They can be used to shorten your blog posts so that only part of the entry — usually the introduction or a summary of the post — is displayed, instead of the entire entry. Using excerpts is completely optional.
Depending on the theme you have activated, excerpts you assign may be displayed on your homepage, RSS feed, or archives page. Your theme will also determine whether or not your excerpt is followed by a link that points readers to the full-length post.
Here’s an example of an excerpt on the homepage of a blog with the Inuit Types theme:
When you click the post title, you’re taken to the full-length post:
Note that the excerpt is only visible on the site’s main blog page (where all posts are shown) but that excerpt text is not visible on the blog post itself.
The Excerpt module can be found to the left of the post editor, with the other publishing options in your sidebar. Just add your text in this field, and then publish your post.
Note that the excerpt feature only works with certain themes. If your theme does not support excerpts, you can use the More tag instead.