wpquestions.com, ID = 3611(2)

<?php
add_filter( 'post_class', 'wpq_filter_post_class' );

function wpq_filter_post_class( $classes ) {

    if( is_singular() ) {

        global $post;

        $taxonomies = get_taxonomies( array( 'public' => true ) , 'names', 'and' );

        if ( is_array($taxonomies) ) {
            foreach ( $taxonomies as $taxonomy ) {
                if ( is_object_in_taxonomy( $post->post_type, $taxonomy ) ) {
                    foreach ( (array) get_the_terms( $post->ID, $taxonomy ) as $term ) {
                        if ( empty($term->slug ) )
                        continue;
                        if ( 'post_tag' == $taxonomy )
                        $classes[] = 'tag-' . sanitize_html_class( $term->slug, $term->term_id );
                        else
                        $classes[] = sanitize_html_class( $taxonomy->name, $taxonomy ) . '-' . sanitize_html_class( $term->slug, $term->term_id );
                    }
                }
            }
        }
    }

    return $classes;

}
?>