There's a very interesting article here
A picture can speak a thousand words. The Not Delia logo is a perfect example of that - and the designer himself said that it was one he was particularly proud of.
But I think that a lot of messages get missed. Did you ever notice how the Amazon logo links from A to Z? I never noticed that until it was pointed out to me. Similarly, most people seem to miss the arrow in the iconic FedEx logo.
What do you think about logos? Have you got one for your business? I've seen it suggested that a professional photograph of yourself is better for branding. I don't agree, I think a great logo is definitely worth having.