It's smaller than you may imagine. Google's great advantage is that they were one of the first to realize that data tends to beat clever algorithms at a certain

It's smaller than you may imagine. Google's great advantage is that they were one of the first to realize that data tends to beat clever algorithms at a certain scale. But for restricted domains there are many techniques that are well-known in academic circles that are not yet mainstream. A "mathy/researchy" feature only requires people versed in that research and math. It is surprising how many jaded IR graduates there are in the valley, looking for an interesting problem to solve.