I've made the same points in the past, if not quite so forcefully (strong language warning!), but can highly recommend to anybody considering a Web project this post by web developer Derek Powazek on the "Spammers, Evildoers, and Opportunists" selling "Search Engine Optimization" (SEO).
"The problem with SEO," he writes, "is that the good advice is obvious [to competent web developers], the rest doesn’t work, and it’s poisoning the web." Powazek's personal strategy for making a website successful is the same as our own: "Make something great. Tell people about it. Do it again."
In his follow-up SEO FAQ Powazek makes a less obvious point that few have caught onto yet: "Social media is rapidly becoming much more important than Google." If you are not engaging (constructively - not spamming) with the communities you serve, on your own website and elsewhere, the money and effort spent on your website are likely to be wasted.