http://wordpress.stackexchange.com/questions/31242/problem-with-conditional-tag-if-empty/31246

wpse31242.php

    <?php
    // First, backup the default $postdata
    $backup = $post;

    // Now, override the default
    $tags = wp_get_post_tags($post->ID);

    // Now, open the if ( $tags ) statement
    if ($tags) {
        $tag_ids = array();
        foreach($tags as $individual_tag) $tag_ids[] = $individual_tag->term_id;

        // Now, setup your custom query args					
        $args=array(
            'tag__in' => $tag_ids,
            'post__not_in' => array($post->ID),
            'showposts'=>4, // Number of related posts that will be shown.    									                                                                      
            'caller_get_posts'=>1
        );
        // Now, perform your custom query
        $my_query = new wp_query($args);

        // Next, open your custom query IF statement
        if( $my_query->have_posts() ) {
            // We have posts, so let's output the opening-containing markup
            ?>

            <h2>Related Posts</h2>						
    			
            <!-- "previous page" action -->
            <a class="prev browse left"></a>
    
            <!-- root element for scrollable -->
            <div class="scrollable" id=chained>   
       
                <!-- root element for the items -->
                <div class="items">
    
                    <!-- post 1-4 -->
                    <div>
    			
                    <?php 
                    // Now, open your custom query WHILE statement
                    while ($my_query->have_posts()) {    									                        
                        $my_query->the_post();
                        ?>
    
                        <div class="relatedPosts"><a href="<?php the_permalink() ?>" rel="bookmark"><?php the_post_thumbnail(array(120,80)); ?></a>
                        <div class="relatedPosts_title"><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></div></div>
    
                        <?php
                        // Now, close the while $my_query->have_posts() statement
                    } 
                    // I'm not sure why this is here?
                    echo '';
                    // Now, output your closing-containing HTML content
                    ?>    
                    </div>
          
                </div>
       
            </div>
    
            <!-- "next page" action -->
            <a class="next browse right"></a>
            <?php
        // Now, close the if $my_query->have_posts() statement
        // and open the ELSE statement, for your no-posts content
        } else {
            ?>
            <!-- If there are no related posts:-->
            <p class="noposts">Sorry, but there are no related posts for this particular entry.</p>
            <?php
        // Now, close the ELSE statement
        }
    // Now, close the if ( $tags ) statement
    }
    // Now, reset the default query
    $post = $backup;
    wp_reset_query();
    ?>