Using SiteUptime for monitoring site downtime.

[apprentice]

Following recent outages from my webhost on one of my domains, including one that lasted over 15 hours (!), I had a go in search of a good free site uptime monitoring tool. The strange thing is that I have two domains from that host, but only one of them is down. So far 'SiteUptime' caught my attention. I am not really bothered with detailed reports; I just want a tool that will tell me when my site is down (especially over substantial periods over 15+ hours!).

The only thing that I wasn't too clear about SiteUptime, is whether there are any side effects in terms of bandwidth usage. From SiteUptime FAQ:

How do you determine if a server is "up"?Our software checks the server response code from your host and if the server response code is "200", "302", "301", "403" or "401", your hostname is considered "up".

Also do you know if the 'pageview' or 'poll' that SiteUptime would perform every 30mins or 1 hour, would affect AdSense which is present on the website? SiteUptime recommends using the root www.example.com for monitoring and not any sub page (although I can't see why not). I am just worried that if it attempts a 'proper' pageload, it would generate AdSense false impressions (and under no circumstances I want that to happen!). Any thoughts?

With Regards