This system monitors the latency of e-mail delivery in java.net every 15 minutes, and plots that in a chart. The delay is measured in minutes. It gives you the historical trend of the delay, as well as the estimate of the likely delay if you send out an e-mail now.
Since mid-2005, we are starting to observe a large latency in the java.net e-mail delivery. For example, when someone commits a change in CVS, the delivery of the change notification e-mail gets delayed. When you post to a mailing list, the distribution of that e-mail gets delayed.
This monitoring is an attempt to better understand the problem, and to reduce the impact it causes to our projects.
This system sends out an e-mail from kohsuke.sfbay inside Sun firewall. The e-mail goes through a Sun mail server, then java.nte mail server, comes back to a Sun mail server, then finally to kohsuke.sfbay itself. The 'latency' measured here is the time it takes for an e-mail to complete this whole journey.
Therefore, it is not the exact delay in java.net; it includes all the latencies in Sun mail servers. (Note that in our experience Sun mail servers have minimal latency, usually in the order of seconds.)