Open Source Network Monitoring at SCALE 5x

High Mobley's article Open Source Network Monitoring at SCALE 5x he talks about the three big Open Source networking monitoring systems who had booths at last month's Southern California Linux Expo - Zenoss, OpenNMS, and GroundWork. The article gives an overview of each project and it's associated company's business model, as well as a short run down of a few of the interesting features of each project.