This is one of my favorite strategies for search engine optimization. For most web sites, there is a lot of untapped potential because they have too few pages, which can only target a few keywords.
Each month, people use over 40,000 different search keyphrases to find the pages on my web sites. My top keyword in this long list represents only 5% of the search engine traffic. Logically, it makes sense that I should spend 95% of my time trying to rank well for other related keywords. Some people will only focus on the "holy grail" top keywords for their industry. While this is important to do, you may find that you can generate more traffic by targeting a large number of less competitive keywords. For many sites, this alone can result in doubling or tripling the search engine traffic.