Thanks a lot for the link. I remember Eliezer arguing with Robin whether AI will advance explosively by using few big insights, or incrementally by amassing encoded knowledge and many small insights. Watson seems to constitute evidence in favor of Robin's position as it has no single key insight:

Ferrucci says his team will continue to fine-tune Watson, but improving its performance is getting harder. “When we first started, we’d add a new algorithm and it would improve the performance by 10 percent, 15 percent,” he says. “Now it’ll be like half a percent is a good improvement.”