On-page optimization for long-tail keywords can result in ranking more than a page higher in search results, compared to half a page optimizing with head terms, according to a study by New York-based SEO & SaaS company Conductor. They also found that long-tail keywords converted 2.5 times better than head terms.
You may remember the uproar from last fall, when SEOMoz purported there was a higher correlation between LDA scores and high rankings than any other factor. Some took this to mean that on-page optimization didn’t matter. It’s a topic that still pops up now and again; my on-page optimization isn’t working, I don’t know if it’s worth it... on-page optimization must be dead.