Selective Dissemination of Information (SDI) is a highly personalized service. It is a method of supplying each user or a group of users with references of documents or abstracts relating to their pre-defined areas of interest selected from documents published recently/received during the period in question.

This service saves the user the effort and time of having to scan through a number of publications, and to choose the documents of interest to him. The basic concept behind SDI is the matching of information/documents with the profile of each user or group of users with same interest.

A user profile and document profile are two important components of the SDI service. Then the matching items are brought to the attention of the user. The same activity can be performed effectively with the help of a computer.

During the process of SDI, the user profile which comprises of a set of key words organised as meticulously as the system permits, describe the subject of interest, in accordance with the keywords that appear on the documents. A document is selected when two key words coincide. In an automated environment, once a search profile of the user is created and saved, relevant information is sent to the researcher automatically (and the selected databases/catalogues are updated).