Out of curiosity, how does this work with project-based courses where the students design their own projects? Or do those not exist?
At least in the kinds of CS masters projects I'm familiar with, they tend to require a lot of one-on-one meeting time, which seems like it would be hard to scale up. It's certainly possible to do online, so online vs. physical isn't really an issue. But if one of the goals of offering these programs online is also to massively increase student:teacher ratio (as GT seems to be indicating), that seems like it would present a problem for individualized projects.
A typical arrangement is that students propose a project, possibly based on some suggestions from the professor. In the ideal case it intersects students' interests with something active going on in the research world or even the professor's lab, so the students and professor might even co-write a conference paper at the end of the course (for the best projects). They meet with the professor a few times to refine the project idea and scope so it's appropriate for the course, likely to be doable, etc. Then they meet a few more times during the project to ensure they're on track, agree on what parts could be cut if time doesn't allow them to be completed as originally envisioned, etc. Finally they do an oral, conference-style presentation of their work/results, and then hand in a report.
The biggest pain has been exam proctoring. It seems to all be done by hand (exams being emailed/faxed back and forth) and I've experienced every point of failure in the system. And strangely the professors always refuse to tell us when the exam windows are... haven't figure that one out yet.
As far as I know, they have the exact same work.
<edit> To address a question below about GT's program, NC State's is practically equivalent to their campus-based stuff. You apply, and are admitted, following exactly the same process as everyone else. After admission, you follow the same rules and processes as everyone else. The one exception I've found -- besides making it easier to study part time and draw out the total duration -- is that professors are usually much more lenient with deadlines for their online students. They know a large percentage of online students are doing it that way because they're working full time (or are deployed military, or any of a plethora of other situations), and they offer a lot of leeway. This helped me & my peers quite a lot.