KEI stands for Keyword Effectiveness Index. KEI is a ranking system based on how popular a key word is and how much competition it has on the Internet. The higher the KEI number, the more popular your keywords are and the less competition they have. It also means that you’ll have a much better chance getting ranked high on a search engine. A low KEI score means not many people are searching for that keyword and it has too much competition. Hence, eliminate all KEI scores with a low number and choose those with a high KEI score. The higher the score, the more profitable your keywords will be to your web site.