Distance education or long-distance learning is the education of students who may not always be physically present at a school. Traditionally, this usually involved correspondence courses wherein the student corresponded with the school via post. Today it involves online education. A distance learning program can be completely distance learning, or a combination of distance learning and traditional classroom instruction (called hybrid or blended). Massive open online courses (MOOCs), offering large-scale interactive participation and open access through the World Wide Web or other network technologies, are recent developments in distance education. A number of other terms (distributed learning, e-learning, online learning, virtual classroom etc.) are used roughly synonymous with distance education. * source: Wikipedia
Approaches that focus on opening access to education and training provision, freeing learners from the constraints of time (asynchronous learning) and place (distance learning), and offering a high level of autonomy and flexible learning opportunities to individual and groups of learners. This flexibility is related with the content of the course, the way in which it is structured, the place, medium and timing of its delivery, the pace of the process and the forms of support available.
Types of open and distance learning are correspondence education, home study and independent study, continuing education, self-education, adult learning, technology-based education, learner-centered approach to education, open learning, flexible learning, e-learning, computer-based training (CBT), and distributed learning. Open and distance learning offers a number of advantages to learners and to providers of learning opportunities.
The concept of open and distance learning has the following characteristics:
1. Separation of trainer and learner in time or place.
2. Institutional accreditation (with the official recognition of a learning institution)
3. Use of mixed-media course ware (use of radio, television, video, audio, computer-based instruction and telecommunications)
4. Two-way communication (allow interaction between learners and tutors)
5. Possibility of face-to-face meetings for tutorials (in libraries, laboratories, and practice sessions)
6. Used of industrialized processes (in a large scale of open and distance learning, labor is divided and tasks are assigned to various staff who work together in course development teams) * source: http://www.click4it.org/index.php/Open_and_Distance_Learning_(ODL)