PeoplesGeek

Monitoring services like www.siteuptime.com or www.montastic.com require a page on your website to monitor.
This plugin provides a virtual target for your monitoring services that does not invoke other plugins (specifically avoiding the Google analytics plugins so that your statistics are not skewed by monitoring calls) 
The two targets provided for the monitoring service are:
<ul>
<li>monitor.htm – via .htaccess and does not use WordPress (but does use PHP)</li>
<li>monitorWP.htm – via WP and so tests the Database etc is working</li>
</ul>

PG Monitor

A virtual target file to be read by monitoring services instead of using a static HTML page.

Pingmeter

You might have a great website, shop or blog. so do your competitor. And they get your visitors when your site is down. It is stressful to have your website down and you get aware of it few hours after your visitors. Be the first one to notice.
Pingmeter ping your website constantly to ensure your website is working fine and take note of ping response speed. If your website timeout or go down, Pingmeter will double check it with our other servers across america, europe, russia and even australia, then notify you via SMS, email or even voice call on your phone.
Monitors can be associated with your website, so Pingmeter keep track of number of online visitors on your websites. and If a monitor go down, it notify you in call about number of your online visitors and record how many online visitors were on your website when this downtime happened.
Pingmeter monitor can scan HTTP, HTTPS, SSL Certificate validation, FTP, SMTP, POP3, IMAP, ICMP, MySQL and custom port pings. Monitors can be parents of a previous monitor, so for example you do not receive multiple alerts if your server go down and bring down HTTP, MySQL and FTP along with it.
Additionally, it can trigger pre-defined rescue actions to automatically recover your website such as modifying your CloudFlare DNS to your backup server or restarting your MySQL, Apache or other services by sending SSH command to your server.
Pingmeter give you a public (or private password protected) status page which you can link on your website so that your visitors can check your service status.
<h4>Read More:</h4>
http://www.pingmeter.com/

Pingmeter Uptime Monitoring

Pingmeter monitors and auto rescues your website during downtimes, so you can relax and focus on what's important. You can configure it to receiv …

PG Monitor vs Pingmeter Uptime Monitoring