// I want newer articles at the end
query_posts('order=ASC');

// If I have posts to display
if (have_posts()):	

	// This special order only applies to homepage
	if ( is_home() ) {
		$myOrderedPosts = array();
		foreach ( $posts as $postIndex => $post ){
			the_post(); 
	
			$myPosition = get_post_meta($post->ID, "posizione", true);
			if ( !empty($myPosition) ) {
				$myOrderedPosts[$myPosition] = $post;
			}
		}
		ksort( $myOrderedPosts );
	}
	else $myOrderedPosts = $posts;

	// Now I have ordered posts, I can display them (the Loop)
	foreach( $myOrderedPosts as $myPosition => $post ){
		
		// This is an internal function that updates pointers for the_title, the_permalink, etc
		setup_postdata($post);
		
		// display article informations and content 
		the_title();
	};
endif;