By default, the excerpt is limited to a length of 55 words. Although this can be adjusted by adding a excerpt_length filter, I didn’t want the content to be cut off half way through a paragraph.

On a more important note, using the_excerpt on pages causes it to generate an automated teaser as there is no excerpt field like that in posts. This means that HTML tags and graphics are stripped from the excerpt’s content.

For me, it was important that formatting be preserved when displaying the content.

If wanting to display a short summary for a list of pages, the_excerpt would be more appropriate in most cases.

http://codex.wordpress.org/Template_Tags/the_excerpt