Pingbreak - Pingbreak is an original and free monitoring service.
cutestat - Website Stats and Valuation. CuteStat.
DownDetector - A simple service to tell you whether a website is down.
Rankchart - Rankchart is one of the unique websites that allows you to examine your websites or watch competitors and locate rich information about website technologies, site reputation, errors, SEO, and ad-word recommendations.
Silent Down - Silent Down is a website uptime and performance monitoring platform - Get notified instantly if your site is down or having performance issues.
Site Worth traffic - Site Worth traffic is a cost-effective site that is introduced to estimate the value, daily page views, daily visitors, and daily revenue of a website.