Discussion Board, Blogs, Email are all forms of asynchronous communication.
Discussion boards are an excellent way to communicate, participate, journal and discuss with others in the course. This tool allows an opportunity for every member to post there thoughts, feelings and viewpoints while encouraging critical thinking skills; reflective in nature. They force students to read other perspectives and carefully consider a response In addition, online discussion boards offer these individuals a tool through which they can actively participate in the class without feeling the overwhelming anxiety they may feel with many sets of eyes on them.The use of discussion boards is an active method of learning, contrasted with the traditional lecture model that is much more passive. As many research studies have shown, active learning is more powerful than passive learning at getting students to learn, retain, and apply course content to novel and practical situations.
I believe that the main benefit of asynchronous (not real time) communication is that you can join and read forums at any time convenient to you, catching up with messages already posted. You can reply at once, or go away and think about your answer before coming back to reply; or indeed, as in a real discussion, you can simply listen without contributing at all. Discussion boards are generally archived, so you can print a particularly interesting or relevant discussion, equally you can return to it at a later point when further contributions may have been made.
Additional features, such as enabling ‘anonymous’ posting, ensure that what one may feel is a ‘stupid’ questions can be asked with impunity.