Checkspeed.org is a website that provides tools to check internet speed. It uses both active and passive techniques to monitor bandwidth. Active techniques involve sending probe packets into the network to gather data, while passive techniques analyze existing network traffic. The site offers internet speed checking tools that users can access at http://www.checkspeed.org to test their bandwidth and see if any optimizations can be made to improve speed. Internet service providers also use monitoring to track bandwidth usage on their networks and ensure connections are performing adequately.