Using a bad definition of "A-level performance" obviously makes the idea of only keeping A players sound like a bad plan. Individual performance evaluations should create incentives that are aligned to company incentives.

- Evaluating performance based on effort fails to incentivize output totally; a high performer who works 9-5 is foolishly ranked underneath a mediocre performer who stays overtime: the mediocre performer will be around forever--the high performer will find a better job.

- Evaluating performance based on high quantity of output without regard to long-term viability (quality) of the output incentivizes reactionary behavior and leads to technical debt: over time, even your high performers won't be able to produce good output in a timely fashion because there is nothing sound to build upon.

If the incentives are aligned, "performance" at an individual level means increasing performance of the team and company, and involves the quantity of high-quality output (ignoring low-quality output) and the degree to which an individual enables the rest of the team to produce high-quality output.

I think the Slashdot comment totally misses the mark on how Netflix defines performance.