Among your switches you have an option to turn on google pagerank. Google doesn't provide an API for the pagerank, and automated queries outside of the API violate google's terms of service. This is why the option is off by default, and it's recommended that you leave it off. If you turn it on, you take responsibility for your actions. The option is only included because other scripts include it and some customers want to take the risk.

If enabled, pagerank will be calculated at the time of link submission. Preexisting links will be slowly updated at timed intervals (one link approximately every 10 page loads) in order to prevent traffic spikes that could cause google to ban you. You can get pageranks updated quickly by regenerating them, but this will very likely cause google to ban you, such that you'll never be able to display a pagerank again -- regenerate them at your own risk.

To get already-calculated pageranks updated you can set an $autopagerankon = true; tweak in your tweaks.php file. This will update a random one every 20 page loads. Note this increases chances of google banning you, but keeps the chances less than when you regenerate.

A sort option will automatically appear to sort by pagerank, and pageranks will show up next to links in the listings.