I wrote a roundoup of articles explaining why carousels are bad and kill clickthrus earlier. Jakob Nielsen provides some advice on how to design one properly if you really must have one.

Summary: Carousels allow multiple pieces of content to occupy a single, coveted space. This may placate corporate infighting, but on large- or small-view ports, people often scroll past carousels. A static hero or integrating content in the UI may be better solutions. But if a carousel is your hero, good navigation and content can help make it effective.

From: Designing Effective Carousels

This question came up yesterday when Sandy and I presented at DC Web Women, an Introduction to  PHP [slides]. I couldn\'t come up with a coherent set of arguments at the time, in a way that I could explain easily. These posts do a better job, first a general programming article on the subject:

Implicit coupling -- A program with many global variables often has tight couplings between some of those variables, and couplings between variables and functions. Grouping coupled items into cohesive units usually leads to better programs.

From: Global Variables Are Bad And a PHP specific article full of excellent examples

You may have heard that globals are bad. This is often thrown around as programming gospel by people who don\'t completely understand what they\'re saying. These people aren\'t wrong, they just don\'t often program what they preach. I\'ve lost track of the number of times I\'ve had the \"globals are bad\" conversation with someone (and been in agreement) only to find their code is littered with statics and singletons. These people are confusing globals (as in the \$GLOBALS array) and global state.

From: Why global state is the devil, and how to avoid using it - TomNomNom.com

Recently, I needed to migrate some WordPress blogs to another system. WordPress provides a handy way to export content in its WXR format. However, it\'ll export all comments, whether approved or not. This is good from a data backup standpoint, but I didn\'t need to import these. They were also bloating the XML file and affecting how long it took my import to process.  I needed a way to remove unapproved comments, the following code will do that using PHP\'s DOMDocument extension to walk an input file. The cleaned up content is sent to STDOUT so you can pipe it to another file to save.

recover = TRUE;
$doc->load($infile);

$comments = $doc->getElementsByTagName('comment');
$to_remove = array();

foreach ($comments as $comment) {
    if ($approved = $comment->getElementsByTagName('comment_approved')) {
        if ($approved->length > 0) {
            $app = $approved->item(0);

            // can't remove nodes while looping
            if (0 == $app->nodeValue) {
                $to_remove[] = $comment;
            }
        }
    }
}

if (count($to_remove)) {
    foreach ($to_remove as $elt) {
        $elt->parentNode->removeChild($elt);
    }
}

$doc->formatOutput = true;
$doc->preserveWhiteSpace = false;
echo $doc->saveXML();