There are some inherent problems to the way wp-cron works. Sometimes you want to disable it and run your own (real) cron instead. This is usually quite simple, just disable wp-cron and set up a job that pings your sites wp-cron.php file on a regular interval. The problem comes when you have a multisite installation and need to ping alot of different sites wp-cron.php file. This plugin helps with that problem by creating a file with a list of url’s to all wp-cron.php files in a WordPress multisite installation.