Bottom line: The Keywords field continues to be an option that can help, but not hinder your search engine optimization (though how much it helps is questionable).
Though we have long suspected that the Meta Keywords field on the SEO tab in the Big Tree CMS had little effect in search engine optimization, recent research confirms that suspicion. Many search engines no longer use this field in their complicated algorithms to rank sites for relevance and importance. Historically, Web developers abused this field to add keywords multiple times in an attempt to increase the relevance of their site in a search. Some developers also added inappropriate keywords to boost popularity.
The one place it was recommended to still consider using the Keywords field related to adding search terms that you may not want to include in the page content, such as common misspellings of words or terms that people may use but that you do not wish to reference in your text. For instance, on our campus it is preferred to talk about residence halls instead of "dorms." However, many prospective students may search on "dorms." Rather than using the undesired term in the text of the page in order to help search engines find our residential life pages, we could add the term "dorms" to the Keywords field to increase visibiilty of this page to search engines. It may not impact the ranking, but it may increase visibility.