EDIT to explain what it is: In getwork days, the pool provided you a single unit of work, you finished it, and asked for more. Discarded was a figure of how much work you had asked for that you never got to use due to longpolls making it obsolete. In GBT/Stratum, pools don't provide you with a unit of work, but they provide you with a template to make work locally.
Is there a good plain english write up explaining pools and how they operate or is it all programmer-speak gobbledegook ?
My inclination was that a pool just divided the potential solution space amonst live workers and gave them alll something to do
Is that anywhere near correct ?
That's pretty close to it. Then it divides the rewards up among the workers in some sort of proportional manner equal to the work provided. Which proportional manner used is in the fine details. Most are pretty fair. Some are subject to abuse. The one used here is one of the fair ones.