Complex sentence: Oringinally a phrase related to library and information science, Selective Dissemination of Information, or SDI, refers to automated searches that alert the user to the availability of new information meeting the user's specified keywords and search parameters.
Split into simpler sentences: Oringinally a phrase related to library and information science, Selective Dissemination of Information, or SDI, referes to tools and resources used to keep a user informed of new resources on specified topics. These sytems provide automated searches that inform the user of the availablilty of new resources meeting the user's specified keywords and search parameters.