I advise against this as all search engines have programs in them now to remove sites that do this. It worked well in the 90's but no longer. The best way to increase your searchability now is to have good content and get referenced by reputable directories.
Well, according to research, some of the most searched phrases are of a sexual nature, but besides these, the following terms are frequently searched: diet, weight, improvement, free, money, broke, job.
