I'd guess that most people who read this blog know about Seth Godin. I'd also guess that they'd assume that most people in their field would know too. But if you ask around, you'd be surprised how many people don't. Try it this weekend.
It's always good to challenge assumptions and it's also good to realise that achieving great marketing success does not involve the ubiquity for which you're striving and which seems so out of reach. It may be a numbers game, but the numbers aren't as daunting as you might think.