Malcolm Knowles, informal adult education, self-direction and andragogy
“Several important differences are found between the interests in organized classes and the interests in lecture, forum and club programs. In the first place, the former are likely to be stable, long-term interests, while the latter are more transitory. In the second place, lectures, forums and club programs are more flexible than organized classes. In a program series the topics can range from pure entertainment to serious lectures, while an organized class is necessarily limited to a single subject-matter area. Third, the lecture, forum, and club types of programs generally require less commitment of time, money and energy from participants than do organized classes. As a result they are likely to attract people with somewhat less intense interest.” (Knowles 1950: 24)

In addition, they are likely to attract people with different motives.  For instance, when I first moved to Coatesville, Pennsylvania, I took an archaeology class through a local adult education program, partially because I was interested but also because I was hoping to meet some new people.  So, I was using learning in a social way.  I didn’t really meet anyone but I did learn a bit about local archaeology and Native Americans.