Today, there is significant sharing of information artifacts among users on various social media sites, including Digg, Twitter and Flickr. An interesting consequence of such rich and extensive social interaction is the evolving nature of “roles” that are acquired by users over time, in the context of variegated communication activities, such as commenting, replying, uploading a media artifact and so on. In this paper, we investigate the discovery of two roles that define information dissipation: disseminators and receptors. We propose a computational framework based on factorization of stacked representation of activities and test the outcomes on a dataset from Digg. Experiments show that our approach can, interestingly, reveal correlations with user activities occurring at a future point in time. Categories and Subject Descriptors J.4 [Social and Behavioral Sciences]: Sociology General Terms Algorithms, Experimentation Keywords Information diffusion, information disseminators...