It was kind of a mix of stack ranking, fire X% on a periodic schedule, and up or out, you've got X years to get promoted or you'll be fired. Microsoft says they stopped stack ranking, but it's not clear if they did. Facebook says they don't force a ratings curve, but they did while I was there. Just because something has fallen out of favor and companies acknowledge that it's fallen out favor doesn't mean they don't do it.
I worked at Microsoft when stack ranking was “eliminated”. Groups still stack ranked (at least mine did) but they had more local control over the process and distribution rather than having to follow one company wide system. Old habits die hard.
Maybe it’s different now, but I doubt it. Any place that pays for performance has to differentiate rewards in some way.
