Related posts widget or plugin needed

@Scott B,

It looks like they are using a related posts query based on category. When a single Item (post) is being displayed the query looks up the category id then displays posts from the same category.

Add The following code to your sidebar or even to the bottom of single.php depending on where you want to display the “Related Posts”

<!--Begin Related Posts-->
    <?php
        if ( is_single() ) :
        global $post;
        $categories = get_the_category();
        foreach ($categories as $category) :
        $posts = get_posts('numberposts=4&exclude=" . $GLOBALS["current_id'] . '&category='. $category->term_id);
        //To change the number of posts, edit the 'numberposts' parameter above
        if(count($posts) > 1) {
    ?>

    <div class="widget" id="more-category">
    <h3 class="widgettitle"><?php _e('More in',''); ?> &#8216;<?php echo $category->name; ?>&#8217;</h3>
    <ul>
    <?php foreach($posts as $post) : ?>
    <li><a href="https://wordpress.stackexchange.com/questions/1092/<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
    <?php endforeach; ?>
    </ul>
    </div>

    <?php } ?>

<?php endforeach; ?>
<?php endif; ?>

<!--/related posts-->

What this is doing is first getting the category of the current post being displayed, omitting the current item from the query, then checking to make sure there are more than 1 posts in that category.

If there are then it will output “More in Your category name” followed by the permalink to the post. If you wanted to show the featured image you could change the last section to look like this:

<div class="widget" id="more-category">
    <h3 class="widgettitle"><?php _e('More in',''); ?> &#8216;<?php echo $category->name; ?>&#8217;</h3>
    <ul>
    <?php foreach($posts as $post) : ?>
    <li><?php the_post_thumbnail(); ?><a href="https://wordpress.stackexchange.com/questions/1092/<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
    <?php endforeach; ?>
    </ul>
    </div>