I have a client whose site/blog is based on the theme Web 2.0* 1.5.0 by Neil Merton. (All of Merton's websites are either gone or 403)
The Problem:
When linking to the site or a page of the site in Facebook, the page's content is not displayed, but a single line: "This is the personal website of..." followed by the name of the site.
I was able to narrow the facebook excerpt problem down to this theme in two ways:
1) I did a google search for that phrase this is the personal site of, and found other sites linked in facebook displayed that. and yes, the theme was Web 2.0* (plus, I conducted my own paste link tests of those other sites in facebook to confirm)
2) Also, looking in the header.php file, I found the exact phrase in the meta name="description" content="" part of the file:
<meta name="description" content="This is the personal website of <?php bloginfo('name') ?>." />
Deleting the description resulted in displaying some CSS code in Facebook, so I couldn't just delete it. How to fix?
The problem described in Facebook's terms:
This page on facebook's Help Center (see "I don't have a preview for my link") described Facebook's need for 3 meta tags: title, name, and link_rel="img_src" pointed further to the fact that I'd HAVE to come up with a replacement of that existing theme code.
The solution:
I found the code to replace it on this page at wordpressapi.com: Customize meta description in wordpress theme or website for SEO.
Not just for SEO, but for Facebook.
Here's the code that I used...
replace
<meta name="description" content="This is the personal website of <?php bloginfo('name') ?>." />
with this:
<?php if (is_single() || is_page() ) : if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
<meta name="description" content="<?php the_excerpt_rss(); ?>" />
<?php endwhile; endif; else : ?>
<meta name="description" content="<?php bloginfo('description'); ?>" />
<?php endif; ?>
So. Originally, this stumped me. I searched here but did not find the solution.
Now I am writing this up for the benefit of the next person who encounters this baffling problem.