All I'm saying is that cron jobs are usually "calls" to server - telling it to update at this time, and at this frequency [every x minutes, etc]. So, if you have like 1,000 users online and they're doing 20,000 actions that requires 20,000 cron jobs, you strain the server - because like I said before, it calls to the server at the criteria(s) you set. The server talks to these cron jobs and the cron jobs tells the server to do this, and vice versa.