"It will help you recognize a big idea if you ask yourself five questions:
(1) Did it make me gasp when I first saw it?
(2) Do I wish I had thought of it myself?
(3) Is it unique?
(4) Does it fit the strategy to perfections?
(5) Could it be used for 30 years?"

— David Ogilvy in “Ogilvy on Advertising”

(Source: inextremis.be)