What does it do?
k-means creates groups from a set of objects so that the members of a group are more similar. It’s a popular cluster analysis technique for exploring a dataset.
Why use k-means?
k-means can be used to pre-cluster a massive dataset followed by a more expensive cluster analysis on the sub-clusters. k-means can also be used to rapidly “play” with k and explore whether there are overlooked patterns or relationships in the dataset.