"The most important word in the vocabulary of SEO is TEST."
"Never stop testing, and your SEO will never stop improving."
"SEO people who ignore research are as dangerous as generals who ignore decodes of enemy signals."
David Ogilvy on Paid Reviews
"There is no need for advertisements to look like advertisements. If you make them look like editorial pages, you will attract about 50 per cent more readers."
What do you think about a site marking those links nofollow?
"It strikes me as bad manners for a site to accept one of my advertisements and then attack it editorially – like inviting a man to dinner then spitting in his eye."
David Ogilvy on SEO Clients
"The relationship between a company and their SEO agency is almost as intimate as the relationship between a patient and his doctor. Make sure that you can life happily with your prospective client before you accept his account."
"Many companies secretly question whether SEO really helps their site, but are vaguely afraid that their competitors might steal a march on them if they stopped."
"I avoid clients for whom SEO is only a marginal factor in their marketing mix. They have an awkward tendency to raid their SEO appropriations whenever they need cash for other purposes."
David Ogilvy on Blogging & Content
"The headline is the 'ticket on the meat.' Use it to flag down readers who are prospects."
"On the average, five times as many people read the headline as read the body copy. When you have written your headline, you have spent eighty cents out of your dollar."
"I… I don't know the rules of grammar… If you're trying to persuade people to do something, or buy something, it seems to me you should use their language, the language they use every day, the language in which they think. We try to write in the vernacular."
David Ogilvy on Your Users
"What really decides users to buy or not to buy is the content of your site, not its form."
"The consumer isn't a moron; she is your wife."
Note: as Mr. Ogilvy has passed away in 1999 the above obviously isn't an interview with him. The above are actual quotes from Mr. Ogilvy made applicable to SEO by replacing words such as advertisement and consumer with SEO or user. I find it fascinating to see how relevant his statements are.