Sending notifications is a common task in any web application. In this scenario, we have subscribers who want to receive e-mail updates about forum activities. In Chapter 9, Enhancing the Power of Open Source Libraries and Plugins, we created a simple e-mail notification system on post publish for sending e-mail notifications for topic creators and administrators. Using the same technique used for sending forum topic updates can become impossible due to the large number of subscribers. Therefore, we will take a look at the scheduling features of WordPress for automating the notification sending process.

As a developer, you might be familiar with cron, which executes certain tasks in a time-based manner. WordPress scheduling functions offer the same functionality with less flexibility. In WordPress, this action will be triggered only when someone visits the site after the scheduled...