I will UPDATE this post every time i discover a new one!

1. Count system for post in wordpress

   This will create automatically a new Custom Field for your post count, called “count_page_hits”. If you want to know how to display them visit: http://codex.wordpress.org/Custom_Fields

   function count_page_hits() {
    if(is_single()) {
      global $post;
      $count = get_post_meta($post->ID, 'count_page_hits', true);
      $newcount = $count + 1;
   
      update_post_meta($post->ID, 'count_page_hits', $newcount);
    }
   }
   add_action('wp_head', 'count_page_hits');

   Source: Bavotasan.com