on one of my sites, i have 30 or so long tail keywords I'm targeting, all basically some variation of the main keyword. I'm running an almost EMD. All of my pages are indexed and webmaster tools shows three of my main keywords as the most relevant keywords on my site. Why then, would i rank only for some of my long tails and none of the main keywords even show up in the top 1000? I've done my kw research and I would have expected the main keywords to at least show in the serps. Anyone experience this before or have any ideas why this may be?