What is a Meta Keyword tag?
The Meta Keyword tag is a deprecated meta tag that was used by search engines to identify the topical content of a webpage.
If used, meta keyword tags would appear in the <head> section of a webpage:
Should Meta Keywords still be used for SEO purposes?
In 2009, Google announced that Meta Keywords were not a ranking factor and had not been a ranking factor for a number of years. Not only have meta keywords been completely devalued, but they are considered a spam signal and have the potential to negatively impact your rankings.
Meta keywords became a spam signal because they were heavily abused by webmasters. The reason they were abused and heavily spammed is that it used to be very easy to get a webpage ranking simply by including meta keywords for terms you wanted to rank for.
If you own or are working on a website that still uses meta keyword tags, it is strongly recommended that you delete them. Don’t consider using meta keywords on new sites or pages your are working on.
Does this mean I should stop using all Meta tags?
No. This does not mean that Google ignores all meta tags. Meta description tags are still used by Google to display a description of your webpage in the search results and title tags are still considered to be a strong on-page ranking factor. Meta robots tags are also still very important in telling search engines how to crawl and index your site.
Will Meta Keywords make a comeback?
No (at least not in a positive way). Search engines are far more advanced than they were back when meta keywords mattered. Meta keywords will never make a comeback as a positive Google ranking signal.