Why machine learning and understanding searcher intent is so important to search

Search is not simply about keyword density and the number of links to a specific page, it is much more complex now. In our interview with Microsoft's Christi Olson and Fabrice Canal, on Live with Search Engine Land about What SEOs need to know about Bing Webmaster Guidelines, we spoke about how Bing ranks content and the importance of semantic and searcher intent. Fabrice Canal, Principal Program Manager at Bing, Microsoft, said "it's all about machine learning" when I asked him what is not a Bing ranking factor. "So this is all about kind of the magic of machine learning where obviously the engineers can go deep to understand exactly what is happening," he said. There is this feeling that when machine learning is running the search rankings or any model, that you cannot debug it.