bjf123
The site had a few ways to make money.
1: Tool Points. For a while you could buy tool points to skip ahead of the queues for their Line Quality tests, as well as pay Tool Points for ongoing line monitoring. All of those testing suites were hosted in Amazon EC2. Minus the Line Quality test which was custom, the Line Monitoring service was basically automated rrdtool.
2: Advertisements. The site had them. Granted, many people on that site probably used an Adblocker, so they weren't visible anyways.
3: Premium. The site had a Premium Member feature where for $10 you could upgrade your account and go Ad-free and get other perks like priority access to the testing tools, especially with the old Speed Test (not the newer Buffer Bloat one, but you had more customization options to eat more bandwidth). I don't know if the site supported Gifting Premium to users, but I remember years ago logging in one day to find my account had been upgraded by someone or something.