The doctoral thesis studied the behaviour of scientists on Internet profiles. The scientific community is founded on communication. The advance of research, the evaluation of research results, the reputation of individual scientists - all rest on constant interaction among the community members. The Internet, as a flexible channel for world-wide communication, has a considerable potential for the scientific community. Besides often discussed consequences for scientific publishing, the Internet also offers new opportunities for self-presentation of scientists. In this thesis, the online presence of scientists was studied with a 'positive lens', concentrating on how the Internet can be used to enhance scientists' individual self-presentation. The doctoral thesis consists of five essays: an overview and four essays documenting separate research projects. The research was founded on the radical constructivist understanding of reality. It was classified as connected to three areas: research on science communication, research on digital identity, and research on generation of online content. Viewing the existing literature in these areas, three focal points were identified, which informed and guided the formulation of research aims and the implementation of research projects: focus on Internet self-presentation, assumption of strategic importance, and need for a holistic view. The aims of the thesis were (A) to develop a holistic understanding of scientists' Internet presence, (B) to study behavioural patterns on scientists' Internet profiles, and (C) to develop an instrument to support the development and management of scientists' Internet self-presentation. Based on these aims, four research projects were carried out. Each project pursued own research questions or objectives using suitable methods, yet all contributed to the overall aims of the thesis. Thus the thesis presents conceptual, empirical, and applied findings resulting from a multi-method approach and contributing both to research on Internet self-presentation as well as to practice in the management of online presence.

Product information search has become one of the most important application areas of the Web. Especially considering pricey technical products, consumers tend to carry out intensive research activities previous to the actual acquisition for creating an all-embracing view on the product of interest. Federated search backed by ontology-based product information representation shows great promise for easing this research process. The topic of this thesis is to develop a comprehensive technique for locating, extracting, and integrating information of arbitrary technical products in a widely unsupervised manner. The resulting homogeneous information sets allow a potential consumer to effectively compare technical products based on an appropriate federated product information system. / Die Produktinformationssuche hat sich zu einem der bedeutendsten Themen im Web entwickelt. Speziell im Bereich kostenintensiver technischer Produkte führen potenzielle Konsumenten vor dem eigentlichen Kauf des Produkts langwierige Recherchen durch um einen umfassenden Überblick für das Produkt von Interesse zu erlangen. Die föderierte Suche in Kombination mit ontologiebasierter Produktinformationsrepräsentation stellt eine mögliche Lösung dieser Problemstellung dar. Diese Dissertation stellt Techniken vor, die das automatische Lokalisieren, Extrahieren und Integrieren von Informationen für beliebige technische Produkte ermöglichen. Die resultierenden homogenen Produktinformationen erlauben einem potenziellen Konsumenten, zugehörige Produkte effektiv über ein föderiertes Produktinformationssystem zu vergleichen.