1. A system comprising a processor for processing a set of social media (SM) streams, comprising: a user interface for selecting a plurality of different SM streams, the selected plurality of different SM streams forming the set of SM streams, and for entering a username and password for each different SM stream; a stream unification system that creates a single unified stream by interleaving the set of SM streams; a content filtering system that selects relevant content items from the single unified stream based on a plurality of filtering definitions inputted via the user interface and generates a unified filtered SM stream for each filtering definition in the plurality of filtering definitions using selected content items, wherein each filtering definition includes a time period during which the unified filtered SM stream is to be displayed; and an output system that outputs each unified filtered SM stream to a user display, the output system: generating a portal page; displaying a separate window on the portal page for each unified filtered SM stream, each window displaying a respective unified filtered SM stream on the portal page only for the time period included in the filtering definition used to generate the unified filtered SM stream, the output system adding the window to the portal page at a start of the time period and removing the window from the portal page at an end of the time period; and displaying an advertising banner on the portal page, the advertising banner displaying advertising content based on the plurality of filtering definitions inputted via the user interface.