The admin bar was introduced in WordPress 3.3. Many people find the admin bar helpful, but is it really needed for blog users that aren’t admins? When you are just a contributer, it is not really necessary so here is a simple piece of code to add to your functions.php file to enable the bar for admins only.
if (!current_user_can('manage_options')) { add_filter('show_admin_bar', '__return_false'); }