In a teaching experiment, 16 face-to-face and 11 e-mail Finnish university students engaged in an argumentation course. The 19 students of the control group did not study argumentation. The course involved two lectures, exercises with argumentative texts, and face-to-face or e-mail seminar discussions based on these texts. The topics of the texts were: (1) sex roles and equality in education; (2) discipline problems in school; (3) the compulsory teaching of Swedish in school (a controversial educational topic in Finland); and (4) physical punishment as a child-rearing method. Free debate, role play, problem-solving, and panel discussion were the devices used in organizing the course. The level of the students' argumentation skills were measured before and after the course. Results indicated that the e-mail studies sharpened students' skills in identifying the relevant grounds from an argumentative text and choosing the correct grounds from different alternatives, while the face-to-face students improved in putting forward counterargumentation. The study suggests that argumentation skills can be promoted by short-term e-mail and face-to-face teaching and that practicing argumentation in different leaning environments develops different kinds of argumentation skills. The study also suggests that, in comparing different learning environments, relevant research questions seem to concern matters of dissimilarity rather than of superiority. (Contains 26 references.) (Author/MES)