The old correspondence courses, in which teachers and students used the U.S. mail to send course material back and forth, were an early and low-tech model of distance education. Technology currently being used to deliver DE includes interactive video and TV, satellite transmissions, cable broadcasting, CDs, and, of course, the Internet. Some of this distance learning is synchronous, meaning that the instructor and students are participating at the same time but in different places. Threaded discussions allow people to respond to a given discussion question over a given period of time, allowing, for example, people to post their first responses over a couple of days and then respond to each other over the next few days. One issue in the design of a distance education program is whether or not a class involves a cohort group as part of the learning experience.
Cohorts are simply people participating in an experience together.
For shorter types of educational programs, such as a two- hour program delivered via satellite, cohort groups are less important. You could probably watch a program like that alone and have a good learning experience. Some distance education is in fact designed to be undertaken alone, such as a self-paced tutorial delivered on the Web. On the other hand, most people find it difficult to complete a semester-long course or an entire degree program on their own, with no interaction with fellow students. For this type of educational experience, participation with classmates can be critical to your understanding of the material and to your success in the class.