A keyword tag is Meta element that is located within the HTML of a web page. Keyword tags hold eight to ten keywords or keyword phrases that include common misspellings of the main page topic or terms that directly pertain to the content of the page. Keyword tags were popularized in the late 1990s by search engines like Infoseek and Alta Vista, but it was quickly discovered that information contained in keyword tags could be misleading or an attempt to create spamdexing. False keywords could be put into a keyword tag to draw visitors to a spam website and was one of the major reasons that keyword tags were eventually dropped from consideration by all search engines by the early 2000s.

The importance of a keyword tag is a frequently argued point among professionals in the field of search engine optimization. While some believe that using keyword tags can help search engine rankings, other believe that because keyword tags do not have any bearing on the search engines whatsoever that they are pointless to use. When web pages rank for the words contained in the keyword tags, it is generally because those keywords are located elsewhere in the web page, and not because they are in the keyword tag. As of April 2007, the professional standpoint on keyword tags is that they have little to no effect on search engine rankings.

Search engine optimization and keyword tags are a unique relationship because of the small effect that keyword tags actually have. Yet, there are certainly benefits to utilizing a keyword tag on a web page. It can help explore the variations on the main keywords, as well as identifying which misspellings may be the most common when referring to the keywords of a particular web page. In all, using a keyword tag cannot hurt a web page, but there are few benefits as well.