Dear Sulasailor,
The importance of a ring oscillator is thus:
Imagine 3 transistors in a row. If you feed the output (off/on) of the first transistor into the second and its output into the third and then (here's the trick) back to the first you set up a repeating circuit (123 - 123 -123 etc.). In electronic terms this produces an oscillating circuit and it will have a frequency (it will do the repeats so many times per second) and that's measurable. Now, the frequency of the oscillation depends on how fast the digital circuit is working and is therefore a measure of circuit speed in a microchip. Importantly it can compare circuit speed with other chips which have a ring oscillator and so can measure Silicon performance against Gallium Arsenide performance in any range of microchips. Thus, it tells an investing company in the POET concept how much faster a POET chip works than a Silicon equivalent chip - this is a critical factor to investment into the POET concept. Measuring other variables such as voltage, current and resistance during these oscillations also compares power usage.
David.