In this piece, Seth Godin (how does he come up with so many brilliant ideas?) talks about loud interruptions as a way to get peoples attention, but if you read the very short piece in it entirety, what he's really talking about is good design.
A well designed fountain doesn't need a loud sign telling people not step in it, it naturally prevents them from doing so by virtue of its design.
Marketing a design business is the same, you can either scream that you're best (what many firms do) or you can choose a niche, become really good at it and you won't have to yell as loud to convince people to hire you.