So when we talk about this course and its scope our goal is to give you a broad overview of recommender systems or recommendation techniques. And we're focused around the computing of those techniques, the algorithms, the ways in which you take, data on people's preferences and turn that into recommendations, you've gotten an introduction already, when we think about this, course, we try to run the spectrum from completely non-personalized recommendations to recommendations based on content, a variety of collaborative techniques. And our emphasis as you'll see is very heavily on the personalized, and the collaborative on recommender systems that make different recommendations for each person based not only on that individual but on the information we get from a full set of individuals. We've also added a lot of topics that we think you will find interesting often in a form of interviews with experts in the field, sometimes digressions of our own into topics that are interesting, and, we have a core at the center of the course that focuses heavily on evaluation, because computing recommendations and algorithms in the end don't do you a whole lot of good unless you know whether they're any good. And by the time you're done, if you make it through this course, you should have a solid, core in the algorithms of reccomender's systems with a lot of awareness of the things that come around that solid core.