Elevator Pitch/"What Do You Do?" (10-20 seconds)
"What Is This?" (3-5 minutes)
"How Does It Work?"/"What Does It Do?" (10-15 minutes)
The Menu/Function Crawl (30-60 minutes)
Each is geared toward the attention span of the intended reader. The more invested or engaged they are with your subject, the longer they will stay focused on it. The shorter ones are for those who neither one of you are sure is right for your intended result. Later on, you are simply refining the message-maybe even getting around objections.
How do you break down your business writing for the different time frames and attention spans available?
P.S. Oh, and the record for PowerPoint slides? From a trip to IBM Japan, 457 slides-I still keep it to remind me!