<?php
/*
Plugin Name: Simple Taxonomy
Plugin URI: 
Description: 
Version: 1.0
Author: 
Author URI: 
*/

// Attach function to init hook
add_action( 'init', 'simple_taxonomy', 0 );

// Taxonomy function
function simple_taxonomy() {

    // Register the taxonomy
    register_taxonomy( 'simple_taxonomy', 'post',
        array(
            'hierarchical' => false,
            'labels' => array(
                'name' => 'Simple Tags',
                'singular_name' => 'Simple Tags',
                'search_items' => 'Search Simple Tags',
                'popular_items' => 'Popular Simple Tags',
                'add_new_item' => 'Add New Simple Tags'
            ),
            'query_var' => true,
            'rewrite' => true
        )
    );
} 
?>