1. "Is It Down Right Now" monitors the status of your favorite web sites and checks whether they are down or not.

  2. StatusCake | Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring

  3. With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.

  4. Site down outage and downtime reports from SiteDown.co

  5. AlertBot provides availability and performance monitoring from an end user perspective.

  6. Detect is a chrome extension that allows you to track any change on a website.

  7. See if your provider or web service is having an outage or it's just you. Post yours and see other's reports and complaints

  8. SaaS monitoring tool for linux servers and websites. Think up-time robot but with more features.

  9. PHP Server Monitor is a script that checks whether your websites and servers are up and running.