Which meta-tags do I really need?
Posted by John Mueller on May 7th, 2007
Many people have a lot of meta-tags in their pages. These meta-tags in the head-section are usually luggage that they carry around from revision to revision, only to have new tags added as friends and “experts” recognize that some are missing.
Which meta-tags does Google really look at, which ones do I need and which ones should I drop?
The only tags that Google looks at are:
(A typical listing in the search results. What you don’t see here are the pages that have the robots-meta-tag set to “noindex, nofollow” 
)
<title>this is the page title - mygreatsite.com</title>
The title-tag is one of the most important elements on a page. This is the title that is shown in the search results for that particular page. In general, you will have a short description of the page along with the “brand” for your website. Some people like to place the brand in front, others prefer to place it behind the actual title. A good title can make or break the results that a page has in the search engine listings. The words in a title are valued highly by Google when searching for a page that matches a particular result.
<meta name=”description” content=”This is a description of my wonderful page. The quality of this page is exceptional. Many famous people have visited my site and did not complain.”>
The description is often displayed along with the title for generic searches. If you do not specify a description, Google will try to find the best description within your page - however, you would probably choose a better one if given the chance. The words in the description meta-tag are also valued when Google is search for a matching page.
<meta name=”robots” content=”noindex, nofollow”>
<meta name=”googlebot” content=”noindex, nofollow”>
The “robots” or “googlebot” meta-tags can tell the search engine to exclude this page from the search index (or to ignore the links on it). The “robots” tag is generic for all search engines, the “googlebot” one is specifically for Google’s crawler. In the most cases, it does not make sense to specify a different behavior for Google, this is why usually only the “robots” tag is used. The possible values for this meta-tag are: “noindex” (to not index this page), “nofollow” (to not follow the links on this page) and “noarchive” (to not archive a copy of this page). The first two (noindex, nofollow) can be combined with “none”. The default behavior is to include and follow all pages; this does not have to be specified.
One other “robots” value that is support by Google is “noodp”. If your website is listed in the DMOZ / ODP directory, it can happen that Google takes the title and description from that listing if it deems it to be the most relevant. To prevent this from happening, you can set the robots-meta-tag to “noodp”.
Other meta tags
All other meta-tags are irrelevant to Google’s indexing and ranking. The “keywords” meta-tag in particular is not used at all by Google (and only very margionally by Yahoo) . The “revisit-after” meta-tag is unnecessary, as are all the other meta-tags.
More information:
May 11th, 2007 at 10:41 pm
Hmmm, you left out the Google verification meta tag
And maybe mention that “the other” meta tags are of 2 kinds:
1) Those totally ignored by Google - they may be used by some odd user agent for something or other.
2) Those that can affect how robots or browsers generally receive the page content. I’m referring to all those cache control meta tags that seem to cause a lot of confusion. I have no solid knowledge of those and I have found quite a bit of conflicting information on that, so I’d be interested in what you can say about them.