There are two formats used for online programs of study, these are the synchronous and asynchronous formats. The differences between the two deal with the delivery techniques and class schedule.
Synchronous classes require students to login to class at preset times for class lectures or discussions. Multimedia computers with audio and video capabilities may be required for such courses. Students may view lectures in a video format on their screens.
Asynchronous classes permit students to login whenever they wish to complete assignments or participate in class discussions. These types of classes make extensive use of newsgroups for content delivery and class participation.
Programs of study may be exclusively synchronous, asynchronous, or a combination of the two. My undergraduate program at the University of Phoenix was entirely asynchronous. This promoted effective use of time for students and professors alike because participants could login at any time of day to attend class.
A perspective student should contact an academic advisor at the institution being considered to determine the formats for the program offerings. Time constraints may make one type of format more advantageous than the other. My personal preference is the asynchronous format.