If you want comments from your classmates, I can place your assignment in a discussion area where other students can read it and respond. Enlightened by all this commentary, you go on to your next assignment. None of this happens at a set time or place. Online courses are an important development in distance education, but they're not going to make classrooms obsolete. For one thing, online coursework demands at least some skill in telecomputing and word processing.
Administration can be awkward.
The teacher can't depend on deadline pressure to encourage student productivity, and students at a given moment are likely to be anywhere from drafting their first assignment to polishing their last one. Perhaps the biggest drawback is that the medium conveys nonverbal communication very poorly. This narrow expressive range challenges teacher and student alike, which is why computer writing is our first online course. Students need to outgrow the techno-babble that dominates computer culture, and to learn how to write simply, clearly, and briefly. Reading off a monitor is awkward at best, and piling masses of text onto the screen only makes matter worse.