META KEYWORDS are used by Yahoo and several smaller search engines when indexing content
The META KEYWORDS tag is placed in the head section of a web page and it looks like this:
<html>
<head>
...
<meta name="keywords" content="your,comma,separated list,of,keywords and phrases">
...
</head>
<body>
...
</body>
</html>
META KEYWORDS is yet another meta tag important for the SEO of your web pages. However it is much less important than TITLE and META DESCRIPTION. Google has been ignoring META KEYWORDS from the very beginning and Yahoo has announced in Oct/2009 that it is dropping support for META KEYWORDS although after that they said that they are still using it but give it a very low priority . There are still several smaller search engines like Inktomi and Teoma that use this tag when matching user searches against indexed content. Also this meta tag is used by some proprietary web spiders which use META KEYWORDS while scraping the web page data.
This means that even though META KEYWORDS does not have a very high weight in web page ranking it is still a good idea to put that tag in each web page and place some relevant keywords there. Be warned that you should not duplicate the same keyword many times since it could cause the search engine to ignore the whole META KEYWORDS tag.
