The information service performed by the Royal Institute of Technology handles requests from both university users and from industry. Fourteen data bases are currently used for SDI purposes. The system is of a general nature which permits inclusion of various data bases of completely different tape formats. Any combination of elements of a bibliographic record can be searched. As the profile maintenance program becomes an essential element when the number of profiles is building up, an on-line facility for updating has been installed. Special emphasis is placed on the principles for free text searching and on the problems of ordering the printout in such a way that it gives user satisfaction. At present a statistical approach is in operation. Since many data bases have keywords or other subject indicators, a combination of free text search of titles and keywords is often used. There is no significant deviation of the user's reaction when given printout from free text searches or from keyword searches. (Author)