You're most welcome.
would you explain please the difference between " Run a command and fetch URL?
Basically that process is almost the same, the different between this is :
1. Run a command
- It will execute the command through your PHP server.
2. fetch URL
- it will automatically run that URL from the server.
In other word, use either one method also can work properly, but depend on your current server configuration.
If guest user access your site required to enter username and password for the security layer, 'fetch URL' method can't be use.
If your PHP server only allow certain directory folder can be access by public, so this 'Run a command' method is not suitable to use.
And perhaps why it should be run in short intervals like 1 hour.?
May i know what is the reason need to execute this every 1 hour?
Because your site user unable to receive those email notification immediately if someone comment in his stream item or other action.
By the way, you can configure this cron interval from the cronjob configuration page.