A TechCrunch article posted yesterday used AlertSite's Business Benchmarks to compare the performance of some of the top social networking sites, including Twitter, Facebook, and YouTube. Here's a brief explanation of how we obtained those metrics.
These social networking sites are part of AlertSite's home page benchmarks. The home page of each site is loaded at five-minute intervals from 12 geographically dispersed U.S. cities. We are using DéjàClick, which is AlertSite's completely built-into-the-browser monitoring solution.
DéjàClick provides a true Web browser perspective of how long the pages is taking to load as well as any timeouts or HTTP errors. A more detailed explanation of the methodology is available.
We are also planning to monitor some transactional benchmarks in the future.