Keyword stemming is the fine art of extending a keyword by using plurals, suffixes or prefixes. It can also include the addition of words either side to extend the keywords scope. A major factor in search engine optimization is the hunt for relevant keywords that are under optimized by competitors, yet frequently used by searchers.
Keyword stemming for search engine optimization is a great traffic draw for your website. A wider variety of keywords through keyword stemming also avoids keyword stuffing and repetitions that might blacklist a website from a search engine when it is actually not attempting to fool the search engine.