Trying to understand something on one Web site means missing out on whatever is being presented on a million others. We catch the eye, but not necessarily the mind. It has been many, many years since we sat around doing absolutely nothing else while listening to the radio. We routinely do paperwork or send off emails during telephone conversations with business colleagues. Our President is known to have performed impressive multi-tasking feats while lobbying congressional leaders on the phone.
Some activities are inappropriate for multi-tasking.
We might listen to a recorded book while driving to work, but serious reading requires more attention. Gleick informs us that we allocate, on average, sixteen minutes a day for reading. We will not finish many books at that rate. No wonder we all wish we had more time for reading.