There is a thread over at Search Engine Watch forums named SE Relevancy vs. SE Optimization - Round 1 where a member named "relevancy" (yea i know), wanted to pin "Optimization" versus "Relevancy."
As you can imagine, many other members had an issue as to "why these need to be mutually exclusive?" Grumpus, well known from Cre8asite, offers this advice:
Rather than building a relevant site, how about trying this: Make sure your SEO Efforts are Relevant to Your Site and It's Mission. From there, everything will just sort of fall into place (and you won't create any gramatical paradoxes that threaten the very fabric of our existence).
The thread then moves into a direction of defining terms such as SEO, SEM, SEF, Usability, Internet Makreting and so on.