Rule #3: Clear Genre

A Music Video, like Avril Lavigne's "Girlfriend" (yeah, she might have gamed the system, but she's still second for most views on YouTube), is nearly always obvious. If you don't know the title and the singer, the music throughout the whole clip will give it away.

But you probably don't want to compete with Avril. That's cool. If you're making a comedy, the viewer needs to laugh almost right away. Why? Because that's how you prove it's really a comedy (because most comedies are funny). If it's action, you gotta blow something up, or hit somebody.

If it’s a comedy, you need a laugh within 10-15 seconds maximum. It annoys and frustrates viewers if they don’t understand what they’re

watching right away.

And the crucial element is speed.  As the graph below shows, the audience doesn't have time to wait around for you to explain what you're doing:

Audience Attention Span
Video length    % of Audience who watched the entire video
10 sec.                   89.61%
20 sec.                   80.41%
30 sec.                   66.16%
60 sec.                   46.44%
 2 min.                   23.71%
 3 min.                   16.62% 
 5 min.                     9.42%
Source: Tube Mogul

 Tune in Next Week for Rule # 4: Repeatable!!!