Where's the SEO advice for startups?

I read a blog post today that really resonated with me. Rand points out that a lot of startup advice doesn't mention SEO. As someone trying to get a new startup off the ground I've been giving a lot of thought to how best to market it. Now we don't have much money to spend on traditional marketing, and as we are a web based business it makes sense to do most of our marketing on the web. How come others don't consider SEO when planning their marketing campaigns?

I've seen other online businesses cover every bus stop around with expensive advertising, plough money into radio and print, and still not rank on first page in google.

In the world of internet where there are such low barriers to entry (building a website is comparatively cheap compared to starting up a bricks and mortar business) and you are going to be playing in a crowded market place - what are your differentiators?

Will you be ignoring SEO?