Long-tail keywords drive more traffic in aggregate than main category keywords, but they are typically difficult to manage; it's nearly impossible to create a predictive model for their success.
This WordStream post suggests positioning your site's SEO strategy to drive long-tail keyword traffic to the site, but focusing on using mid-tail keywords because the site will gain
better performance. SEO professionals can do this by structuring Web sites to acquire longer-tail traffic by carefully planning interlinking and link-building and content creation strategies to
aggressively target mid-tail keywords.
Read the whole story at WordStream Internet Marketing Blog »