Planners of traditional conferences assume that the primary purpose of conference sessions is to transmit pre-planned content.
The three communication modes used among a group of people are one-to-one (individual conversations), one-to-many or broadcast (presentations and panels), and many-to-many or conferring (discussions). Traditional conference sessions are predominantly one-to-many, with perhaps a dash of many-to-many at question time.
One-to-one conversations are infinitely flexible; both participants have power to lead the conversation along desired paths. Many-to-many conversations are powerful in a different way—they expose the participating group to a wide range of experience and opinions.
In contrast, one-to-many communication is mostly pre-planned, and thus relatively inflexible if the presentation involves a passive audience. At best, a presenter may ask questions of her audience and vary her presentation appropriately, but she is unlikely to get accurate representative feedback when her audience is large. Some presenters can create interactive sessions with significant audience participation, but they are the exception rather than the rule.
Presentations and panels are appropriate when we are training, and have expert knowledge or information to impart to others. But today we have a rich variety alternative methods to train adults. For example: reading books and articles, watching recordings of presentations, and searching for information and downloading answers on the Web.
What can you you not replicate at a face-to-face conference? The spontaneous conversations and discussions! So why do we still cling to conference sessions that transmit pre-planned content, employing the one communication mode for which a variety of alternatives can substitute?