This paper outlines an e-Learning services architecture offering semantic-based services to students and tutors, in particular ways to browse and obtain information through web services. Services could include registration, authentication, tutoring systems, smart question answering for students' queries, automated marking systems and a student essay service. These services--which might be added incrementally to the portal--could be integrated with various ontologies such as ontologies of educational organisations, students and courses. In this paper, we describe a few scenarios in the e-learning domain and illustrate the role of a few services. We also describe in some detail a service doing semantic annotation of argumentation in student essays for allowing visualization of argumentation and providing useful feedback to students. (Contains 9 tables and 6 figures.)