For A More Powerful Performance, Say It Short And Well

Centuries ago great orators often spoke for several hours at a time. But today, when sound bites on television news are the status quo and complex sociological problems are solved in an hour on a television drama, audiences are most interested in speakers who get their points across in a short period of time. Today, great speakers are noted for their brevity.

Boyd, Stephen D. Presentations (2003). Articles>Presentations>Rhetoric