The plural and singular versions of a keyword can mean extremely different things to a customer and to a search engine like Google. These differences can mean the difference between a campaign’s success or failure. There are a lot of factors to consider, but the two most important ones to discuss are 1) the intent of the searcher and 2) and the number of searches.
Making a word plural by adding and “S” to the end of your search word can completely change the meaning and direction of your search. If the plural of your main keyword can mean something different than in the singular, a search engine may decide that the searches represent different needs. In putting your key word into a search engine like Google, if your top ten results appear different between the singular and plural, you should consider which things are more important for your business and make that term most effective.
One version of a keyword will often get more searches than the other, but it is not always the same across the board. A quick way to research what your site’s keyword might be is to use Wordtracker’s free keyword tool and see what you might find.
Overall, plural and singular keywords can be very different in regards to SEO. They are different according to both the customer and to search engines. They can create a variety of searches and direct the searcher different ways. In order to aide your decision between plural and singular keywords, do some keyword research to see what might be best for the target of your website.