This will focus on applications of algorithms for commonly seen retail ads, targeted campaigns with a deep dive on audience segmentation with k-means algorithm. Lifetime Value Prediction, Audience Segmentation and other algorithms are often used in Retail brick and mortar shops as well as e-commerce. We will understand the commonly used ML algorithms and the theory behind clustering algorithms, when to use them too. Further we will go through best practices for implementing such ML algos in scale in real world scenarios. We will also discuss what different roles exist in the data science field.