Clustering with constraints is fairly recent trend of development which allows a domain expert's interference in the clustering process. The authors use modified objective function of k-means algorithm to incorporate constraints to cluster twitter users. In this paper, they generate instance level constraints using normalized cosine measure, do basic filtering and apply domain expertise. They can apply these techniques on any similar data sets like Facebook posts, answers and comments for modeling and clustering the users. By experiments they show that purity of clusters can be improved by applying instance level constraints.