Probably the most common use of clustering is in customer segmentation. The reason is by treating all of your customers as one large monolithic group, doesn't do very well when you're trying to figure out targeted offerings for customers that have different needs. It also allow you to have a more personalized approach when you are doing your marketing or when you're designing your products. Having just one single product for everyone doesn't do as well as having a series of products that meet customers needs in a more targeted way. Now, there are a number of ways to do customer segmentation, and the main difference between them is the kinds of variables that you are using for an input. Often, psychographics are used in order to determine which segments your customers belong to. And the advantage of using psychographic information is that it allows you to understand the motivating factors, and the worldview of your customers much better than looking at something that's relatively benign like demographic information or transactional history. So most marketers like to understand the psychographics of their various customer groups, even if they also look at the demographics, and other metrics around that. It's certainly possible to create a customer segmentation using only demographic variables. And in fact, there are a number of successful segmentation that have done exactly. These ones look at the overall lifestyle, and general purchase behavior, and then using that, they infer the interests of the segments. And so using this can be quite useful depending on what kind of product you have. If you're trying to target quite broad demographic groups, then this can be quite good in allowing you to understand which general groups may be most interested in your product. The other style of customer segmentation is a behavioral segmentation. So instead of looking at attitudes or psychographics, instead it looks at the actual behavior of the group. So this kind of segmentation is quite useful to understand the lifestyles, and actions of the groups based on their behaviors, and give you some insight into how you can effectively reach them. So now you should have an idea of the kinds of segmentations that you can do with customers and how clustering can be used in order to find those specific segments.