I didn't read the whole thread, so forgive me if I've skipped something. However, I want to address the OP.
First, you have to understand that earthquakes are a very complex issue, particularly in California. I'm not aware of what part of the state you're in, but there are parts of the state (the Transverse Range, for example) where stresses are resulting in the rotation of a block of crust the size of some of the smaller Eastern states. In other areas, the stress is more north-south. In others, the stress is extensional--remember, the Basin and Range is a rift zone, akin to Africa's rift valleys. What this means is that there's so much of so many different types of stress that you simply cannot make generalizations like "small earthquakes releave stress" or "no, they don't".
To fully understand what's going on...well, I don't think that's possible at this point. To get an idea of what's going on, you need to understand how rocks react to stress. Basically, all rocks are under pressure, along all three orthogonal axes. Typically, one of these is greater than the others--and when that stress gets too high, or pore fluid pressure becomes high enough to lubricate things enough, the rock pops normal to that axis. This releaves stress along that axis, but that doesn't mean that the rock is no longer under stress. Rather, it means that a NEW axis becomes the one with the highest stress (Sigma 1 in structural geology terms).
I mentioned pore fluid pressure. That's actually a major factor. It takes more energy to move a block of rock the size of a county (particularly something like Riverside or San Bernardino) than it does to break the rock. Pore fluid pressure, however--the pressure of the water and other fluids in the cracks of the rock--can reduce that pressure by pushing the rocks apart a bit. The water is under the same pressure as the rocks (because the rocks are pushing on the water), and that pressure can make things move much, much easier than they can without it.
The other issue is that a small quake can mobilize groundwater or shift stress regimes, and cause a larger fault to cut loose. This means that a small quake can easily cause a larger one--particularly in the San Andreas Fault Zone or other large fault zones.
In short, this is a very, very complicated topic, and one which certainly needs more analysis than "I felt a few earthquakes today".
