If you are taking an online speech course in speech writing, the curriculum will be only slightly different from what you might experience in the classroom. Your professors will still require you to analyze famous speeches and write your own, but instead of listening to lectures, you will have to teach yourself the course content via readings and audio clips of different kinds of speeches.
Speech theory classes online will be the most similar in content to the classes you take on campus. All of the content will be the same, but you will be absorbing it through reading instead of by listening to lectures. Even your exams may be online, though some professors will require you to take the exams in their classrooms on planned dates.
Speech delivery classes are the most affected by the change in educational arenas. They require an evaluation of your physical presence and performance. To compensate for the lack of peer interaction, professors may require you to come in several times during the semester to perform, or to upload video of yourself performing the assigned speeches for grading.
Taking an online speech course allows you to complete your coursework at your own pace, and if you're already chugging along in the workplace, it can help sharpen your professional presentation skills.
An online speech course may not be able to offer you the same learning experiences as the physical classroom will. Because you do not have an opportunity to watch and learn from your classmates' mistakes or questions, you miss out on the interactive component of education, which is a critical aspect of communication education as a whole.