The keywords meta tag allows you to specify which words are most relevant to your webpage. The keywords meta tag looks like this:
<meta name="keywords" content="Write your keywords and keyphrases here, separated by commas">
Your keywords meta tag should be less than 150 characters long, including spaces. Include the primary and secondary keyphrases that appear prominently throughout the webpage.
Caveat: Due to spamming years ago, the keywords meta tag doesn't have much impact anymore on search engine rankings (although every little bit of help counts). Having said that, most of the top-ranked websites for competitive keyphrases still use the keywords meta tag.
In any case, I encourage clients to use the keywords tag, if only as a forcing-function to ensure that their copywriter carefully considers which keyphrases are most important to the webpage.
