Perishable on Twitter

n this function, WordPress differentiates between linked comment signatures and unlinked (empty) comment signatures, formatting output accordingly. As you can see, when the comment author provides a URL, WordPress fashions a linked signature featuring the infamous external nofollow attribute. We need WordPress to further differentiate comment links based on whether or not the author is found on our blacklist. Sure enough, injecting a conditional elseif() statement does the trick:

// [ Nofollow Blacklist ] WordPress 2.0, 2.1, 2.2 >>
function get_comment_author_link() {
	global $comment;
	$url    = get_comment_author_url();
	$author = get_comment_author();

	if ( empty( $url ) || 'http://' == $url )
		$return = $author;
	elseif ( $author   == 'spammy username 1'
			|| $author == 'spammy username 2'
			|| $author == 'spammy username 3'
			|| $author == 'spammy username 4'
			|| $author == 'spammy username 5'
		)
		$return = "<a href='$url' rel='external nofollow'>$author</a>";
	else
		$return = "<a href='$url' rel='external'>$author</a>";
	return apply_filters('get_comment_author_link', $return);
}