A continuous ping to your website won’t inform you when it goes down if you are away from your computer. To know my blog is up all time, I use Uptime Robot to keep me informed when my blog is down so I can re-mediate it ASAP.
Uptime Robot is a FREE service created by Umut Muhaddisoglu, WebResourcesDepot and Daniel Rimille, SSLmatic to monitor your websites every 5 minutes and alerts you if they goes down via email, SMS and Twitter. The interface is fully Ajaxed, easy to setup and fast. You can have up to 50 websites to monitor for a single account. Also, Uptime Robot is made possible to monitor either HTTP or HTTPS web address.