Really Fast SEO Slugs with WordPress plugin (Technical Tuesday)

<?php
/*
Plugin Name: SEO Slugs
Plugin URI: http://www.vretoolbar.com/news/seo-slugs-wordpress-plugin
Description: Removes common words like 'a', 'the', 'in' from post slugs to improve SEO.
Version: 1.0
Author: Andrei Mikrukov
Author URI: http://www.vretoolbar.com
*/
 
/*
Copyright Andrei Mikrukov 2007
 
Licensed under the terms of the GPL version 2, see:
http://www.gnu.org/licenses/gpl.txt
 
Provided without warranty, inluding any implied warrant of merchantability or fitness for purpose.
*/
 
add_filter('name_save_pre', 'seo_slugs', 0);
 
function seo_slugs($slug) {
 
    // We don't want to change an existing slug
    if ($slug) return $slug;
 
    global $wpdb;
    $seo_slug = strtolower(stripslashes($_POST['post_title']));
 
    $seo_slug = preg_replace('/&.+?;/', '', $seo_slug); // kill HTML entities
    // kill anything that is not a letter, digit, space or apostrophe
    $seo_slug = preg_replace ("/[^a-zA-Z0-9 \']/", "", $seo_slug);
    // Turn it to an array and strip common words by comparing against c.w. array
    $seo_slug_array = array_diff (split(" ", $seo_slug), seo_slugs_stop_words());
    // Turn the sanitized array into a string
    $seo_slug = join("-", $seo_slug_array);
 
    return $seo_slug;
}
 
function seo_slugs_stop_words () {
    return array ("a", "able", "about", "above", "abroad", "according", "accordingly", "across", "actually", "adj", "after", "afterwards", "again", "against", "ago", "ahead", "ain't", "all", "allow", "allows", "almost", "alone", "along", "alongside", "already", "also", "although", "always", "am", "amid", "amidst", "among", "amongst", "an", "and", "another", "any", "anybody", "anyhow", "anyone", "anything", "anyway", "anyways", "anywhere", "apart", "appear", "appreciate", "appropriate", "are", "aren't", "around", "as", "a's", "aside", "ask", "asking", "associated", "at", "available", "away", "awfully", "b", "back", "backward", "backwards", "be", "became", "because", "become", "becomes", "becoming", "been", "before", "beforehand", "begin", "behind", "being", "believe", "below", "beside", "besides", "best", "better", "between", "beyond", "both", "brief", "but", "by", "c", "came", "can", "cannot", "cant", "can't", "caption", "cause", "causes", "certain", "certainly", "changes", "clearly", "c'mon", "co", "co.", "com", "come", "comes", "concerning", "consequently", "consider", "considering", "contain", "containing", "contains", "corresponding", "could", "couldn't", "course", "c's", "currently", "d", "dare", "daren't", "definitely", "described", "despite", "did", "didn't", "different", "directly", "do", "does", "doesn't", "doing", "done", "don't", "down", "downwards", "during", "e", "each", "edu", "eg", "eight", "eighty", "either", "else", "elsewhere", "end", "ending", "enough", "entirely", "especially", "et", "etc", "even", "ever", "evermore", "every", "everybody", "everyone", "everything", "everywhere", "ex", "exactly", "example", "except", "f", "fairly", "far", "farther", "few", "fewer", "fifth", "first", "five", "followed", "following", "follows", "for", "forever", "former", "formerly", "forth", "forward", "found", "four", "from", "further", "furthermore", "g", "get", "gets", "getting", "given", "gives", "go", "goes", "going", "gone", "got", "gotten", "greetings", "h", "had", "hadn't", "half", "happens", "hardly", "has", "hasn't", "have", "haven't", "having", "he", "he'd", "he'll", "hello", "help", "hence", "her", "here", "hereafter", "hereby", "herein", "here's", "hereupon", "hers", "herself", "he's", "hi", "him", "himself", "his", "hither", "hopefully", "how", "howbeit", "however", "hundred", "i", "i'd", "ie", "if", "ignored", "i'll", "i'm", "immediate", "in", "inasmuch", "inc", "inc.", "indeed", "indicate", "indicated", "indicates", "inner", "inside", "insofar", "instead", "into", "inward", "is", "isn't", "it", "it'd", "it'll", "its", "it's", "itself", "i've", "j", "just", "k", "keep", "keeps", "kept", "know", "known", "knows", "l", "last", "lately", "later", "latter", "latterly", "least", "less", "lest", "let", "let's", "like", "liked", "likely", "likewise", "little", "look", "looking", "looks", "low", "lower", "ltd", "m", "made", "mainly", "make", "makes", "many", "may", "maybe", "mayn't", "me", "mean", "meantime", "meanwhile", "merely", "might", "mightn't", "mine", "minus", "miss", "more", "moreover", "most", "mostly", "mr", "mrs", "much", "must", "mustn't", "my", "myself", "n", "name", "namely", "nd", "near", "nearly", "necessary", "need", "needn't", "needs", "neither", "never", "neverf", "neverless", "nevertheless", "new", "next", "nine", "ninety", "no", "nobody", "non", "none", "nonetheless", "noone", "no-one", "nor", "normally", "not", "nothing", "notwithstanding", "novel", "now", "nowhere", "o", "obviously", "of", "off", "often", "oh", "ok", "okay", "old", "on", "once", "one", "ones", "one's", "only", "onto", "opposite", "or", "other", "others", "otherwise", "ought", "oughtn't", "our", "ours", "ourselves", "out", "outside", "over", "overall", "own", "p", "particular", "particularly", "past", "per", "perhaps", "placed", "please", "plus", "possible", "presumably", "probably", "provided", "provides", "q", "que", "quite", "qv", "r", "rather", "rd", "re", "really", "reasonably", "recent", "recently", "regarding", "regardless", "regards", "relatively", "respectively", "right", "round", "s", "said", "same", "saw", "say", "saying", "says", "second", "secondly", "see", "seeing", "seem", "seemed", "seeming", "seems", "seen", "self", "selves", "sensible", "sent", "serious", "seriously", "seven", "several", "shall", "shan't", "she", "she'd", "she'll", "she's", "should", "shouldn't", "since", "six", "so", "some", "somebody", "someday", "somehow", "someone", "something", "sometime", "sometimes", "somewhat", "somewhere", "soon", "sorry", "specified", "specify", "specifying", "still", "sub", "such", "sup", "sure", "t", "take", "taken", "taking", "tell", "tends", "th", "than", "thank", "thanks", "thanx", "that", "that'll", "thats", "that's", "that've", "the", "their", "theirs", "them", "themselves", "then", "thence", "there", "thereafter", "thereby", "there'd", "therefore", "therein", "there'll", "there're", "theres", "there's", "thereupon", "there've", "these", "they", "they'd", "they'll", "they're", "they've", "thing", "things", "think", "third", "thirty", "this", "thorough", "thoroughly", "those", "though", "three", "through", "throughout", "thru", "thus", "till", "to", "together", "too", "took", "toward", "towards", "tried", "tries", "truly", "try", "trying", "t's", "twice", "two", "u", "un", "under", "underneath", "undoing", "unfortunately", "unless", "unlike", "unlikely", "until", "unto", "up", "upon", "upwards", "us", "use", "used", "useful", "uses", "using", "usually", "v", "value", "various", "versus", "very", "via", "viz", "vs", "w", "want", "wants", "was", "wasn't", "way", "we", "we'd", "welcome", "well", "we'll", "went", "were", "we're", "weren't", "we've", "what", "whatever", "what'll", "what's", "what've", "when", "whence", "whenever", "where", "whereafter", "whereas", "whereby", "wherein", "where's", "whereupon", "wherever", "whether", "which", "whichever", "while", "whilst", "whither", "who", "who'd", "whoever", "whole", "who'll", "whom", "whomever", "who's", "whose", "why", "will", "willing", "wish", "with", "within", "without", "wonder", "won't", "would", "wouldn't", "x", "y", "yes", "yet", "you", "you'd", "you'll", "your", "you're", "yours", "yourself", "yourselves", "you've", "z", "zero");
}
?>

add_filter('name_save_pre', 'seo_slugs', 0);

    // We don't want to change an existing slug
    if ($slug) return $slug;

    global $wpdb;
    $seo_slug = strtolower(stripslashes($_POST['post_title']));

    $seo_slug = preg_replace('/&.+?;/', '', $seo_slug); // kill HTML entities

    // kill anything that is not a letter, digit, space or apostrophe
    $seo_slug = preg_replace ("/[^a-zA-Z0-9 \']/", "", $seo_slug);

    // Turn it to an array and strip common words by comparing against c.w. array
    $seo_slug_array = array_diff (split(" ", $seo_slug), seo_slugs_stop_words());
    // Turn the sanitized array into a string
    $seo_slug = join("-", $seo_slug_array);
 
    return $seo_slug;