I believe responding to questions promptly is very important especially in media such as message boards or texts.
Attention spans in general are eroding, so catching a student when he or she is inquisitive is like a fisherman feeling a nibble on the line. Setting the hook by guiding a student to an answer is where the inherent fun of teaching lies.
Unfortunately, online interaction is not an equal substitute for face to face interaction. Its strong point is data collection. Tests that monitor how long it takes for a student to answer a question and recognize problem areas are expensive, but are efficient tools for teachers to identify weak areas of the program or teaching style.
In addition, it is comforting for a student to know where he/she has competency, and that valuable time is spent wisely on competencies that are lacking.
