In recent times, microblogging sites like Facebook and Twitter have gained a lot of popularity. Millions of users world wide have been using these sites to post content that interests them and also to voice their opinions on several current events. In this paper, we present a novel non-parametric probabilistic model - Temporally driven Theme Event Model (TEM) for analyzing the content on microblogs. We also describe an online inference procedure for this model that enables its usage on large scale data. Experimentation carried out on real world data extracted from Facebook and Twitter demonstrates the efficacy of the proposed approach. Copyright is held by the author/owner(s).