Beside the classical product domains of digital cameras, dvds or music, recommendation technologies are successively applied in new domains. In Software Engineering, programmers can be supported in the development and maintenance of software, for example, by improving the understandability of software components. A new and rapidly evolving research area is the application of recommendation technologies in the context of Requirements Engineering (RE). RE is one of the most critical phases in the software development process: low-quality and inconsistent requirements have a direct impact on the follow-up phases und are very often responsible for unsucessful software projects. The following results have been developed within the scope of the IntelliReq project (Intelligent Recommendation Technologies for Requirements Engineering):

1. Pro-active support of cooperative development, analysis, and reuse processes in the context of RE on the basis of new algorithms in the areas of content-based recommendation, collaborative filtering, and data mining.
2. Semi-automated detection of dependencies and repair of inconistencies in a given set of requirements on the basis of new approaches in the areas of content-based recommendation, data mining, and explanations.
3. Intelligent, group-based decision support on the basis of new algorithms in the areas of group-based recommendation and knowledge-based recommendation.