I'm not sure that debating is the best form of learning.

If we all study a particular topic and make our own interpretation of the subject matter and then enter into debate with others, it all too often is the one with the strongest personality and/or debating skills whose views become dominant, and not the one who made the most accurate conclusions.

The medium doesn't fundamentally alter the practice. An unregulated online forum is no different from an unregulated offline forum, really. While online debates tend to happen in open forums, that's not inherent either.

Yes, there is a place for online debates in academia. Debates are a great way to stimulate critical thinking and to allow students (and faculty) to better see both sides of an argument.

However, if I were using this as a teaching tool in a class, I would be sure to set up ground rules and keep the debate within the members of my class. Perhaps after the students had some experience, they could venture out into public debates now being able to better evaluate the arguments (or lack thereof) that they encounter.

I think they certainly have the potential to work however its success in teaching depends on those who are debating. At the very least if one goes into a debate with an open mind it's very possible to see a side that is different from a stance they originally took allowing them to broaden their horizons, so to speak, as well as encourage them to do more research on a topic. Often playing devil's advocate can nudge someone to a different realization that they had previously.