This is a bit confusing. I don't suspect Netflix is built using primarily node.js, and I don't see how the Netflix Prize (algorithm for predicting what a person is most likely to want to watch) falls under "scaling".
The idea behind mentioning the Netflix prize is to show the openness and willingness to get a lift on their existing recommendation algorithm. There was a 10+% lift in accuracy. Their ability to open up the data and implement really gives them a competitive edge IMHO. It's a shame there seems to be some regulatory reasons they don't do it any more.