rss - Help needed to make my site as Aggregator in WordPress

Cron is job scheduling mechanism in Unix-based operating systems. It depends on your hosting if you have access to it.

Since WordPress needs to run some tasks periodically it has own PHP-based mechanism called WP-Cron that is both used by core and accessible to plugins.

Basically OS cron is more reliable, WP-Cron is more compatible.

Automatic updates most likely refers to plugin using WP-Cron.

How much this might be issue with hosting depends on:

• hosting policy for background processes
• hosting CPU quotas (and bandwidth quotas if they are low enough and you poll often enough)
• amount and rate of updates you perform