An Introduction to Clustering & different methods of clustering

Have you come across a situation when a Chief Marketing Officer of a company tells you – "Help me understand our customers better so that we can market our products to them in a better manner!" I did and the analyst in me was completely clueless what to do! I was used to getting specific problems, where there is an outcome to be predicted for various set of conditions. But I had no clue, what to do in this case. If the person would have asked me to calculate Life Time Value (LTV) or propensity of Cross-sell, I wouldn't have blinked.