Serendipity
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Jump to navigationJump to searchSerendipity is a user-friendly popular PHP blog
Comment spam
Insert this at the beginning of comment.php to prevent anyone from spamming your blog without being referred from the blog (this prevents spamming from third party URLs and automated software).
$referrer = parse_url( $_SERVER[ "HTTP_REFERER" ] );
if ( $referrer[ "host" ] != $_SERVER["HTTP_HOST"] ) {
echo "Don't post from another server!";
exit();
}