One is time. By their nature, class discussions can take a while to develop. Oftentimes, the most interesting parts of a discussion are discovered long into the examination of a subject. A related obstacle is equal time for all students. Some students speak a lot, and some speak a little, and some might not even get the opportunity to speak. Also, some students may just be reluctant to speak in front of their peers.
Digital or online discussion boards have been used to mitigate these obstacles, but they can often lose focus the longer they go on and the further they become removed from the discussion topic. Discussion or message boards make it difficult to retain the context of the conversation at hand simply by the user-interface of the board itself. This brings me to an excellent solution: NowComment.
NowComment is a free (yes, free) web app that allows for dynamic and engaging discussions of online documents, articles, videos, and more. What sets this educational tool apart from the others are its unique user-interface and features.
NowComment uses a brilliant two-pane user-interface that contains the article or video on the left side of the screen and the discussion of it on the right side. The article or video can be marked with annotations that link to specific discussions and comments about that particular sentence, paragraph, or section. NowComment keeps everyone on literally the same page, and the discussions become more relevant and engaging. Here are two short videos that demonstrate NowComment's awesome features.