A special activity, that became possible nowadays, is the collaborative e-learning and collaborative engineering of learning materials. Such an opportunity is available in educational systems, based on the wiki paradigm. However, Ward Cunningham's wiki paradigm was mainly only applied to unstructured, textual content thus limiting the content structuring, re-purposing and reuse. Some steps in this direction are made by Semantic Web technologies and their combination with the wiki paradigm. In many potential usage scenarios, however, the(semi-)structured educational content (e.g. presentations, questionnaires, diagrams, etc.) should be managed and the collaboration of large user communities around such content should be effectively facilitated. We present the CrowdLearn concept for collaborative engineering of the semantically structured learning objects as well as a model-driven approach to generate the wiki-like application operating in the spirit of CrowdLearn. We implement and evaluate the approach with Slidewiki - an educational platform mainly dealing with slide presentations. The article also comprises a usability evaluation with real students.