So now, you're wondering what the purpose of all this is? Well, mainly, its for testing and practice... Testing people's ability to use their radio, making sure their radios work (and sure enough, there was someone with a dead battery tonight), making sure the repeater is working, its practice for the net control (the person running the net). Sure, there's also some news that is passed along to people. You also heard CERT "FRS" checkins. These, are from the various "CERT areas" in Wrightwood.. before this net, the CERT people have their own net, again, for practice.
During emergencies (which include bad storms), the "net" is activated. This keeps traffic on the repeater orderly, and "on topic". During emergencies, is when people will pass information, or requests for help as needed.
After this net, comes the "simplex" testing net. This means, radio operators talking directly to each other, without the use of a repeater. Why? Same reasons as before, but it also allows us to know better, just who can talk to who, in the mountains, without the aid of a repeater.