Meta element

The keywords attribute was popularized by search engines such as Infoseek and AltaVista in 1995, and its popularity quickly grew until it became one of the most commonly used meta elements.[2]

No consensus exists whether or not the keywords attribute has any effect on ranking at any of the major search engines today. It is speculated that it does if the keywords used in the meta can also be found in the page copy itself. With respect to Google, thirty-seven leaders in search engine optimization concluded in April 2007 that the relevance of having keywords in the meta-attribute keywords is little to none[3] and in September 2009 Matt Cutts of Google announced that they were no longer taking keywords into account whatsoever.[4] However, both these articles suggest that Yahoo! still makes use of the keywords meta tag in some of its rankings. Yahoo! itself claims support for the keywords meta tag in conjunction with other factors for improving search rankings.[5] In October 2009 Search Engine Round Table announced that "Yahoo Drops The Meta Keywords Tag Also"[6] but later reported that the announcement made by Yahoo!'s Senior Director of Search was incorrect.[7] In the corrected statement Yahoo! Senior Director of Search states that "…What changed with Yahoo's ranking algorithms is that while we still index the meta keyword tag, the ranking importance given to meta keyword tags receives the lowest ranking signal in our system … it will actually have less effect than introducing those same words in the body of the document, or any other section."[7] In Sept 2012, Google[8] announced that they will consider Keyword Meta tag for news publishers. Google said that this may help worthy content to get noticed. The syntax of the news meta keyword has subtle difference from custom keyword meta tag; it is denoted by "news_keywords", while the custom keyword meta tag is denoted by "keywords". Google News no longer takes into account keywords announced by news_keywords.[9]

According to Moz, "Title tags are the second most important on-page factor for SEO, after content".[10] They convey to the search engines what a given page is all about. It used to be standard SEO practice to include the primary and the secondary keywords in the title for better ranking. Google has gone through various iterations of showing short or longer amounts of content from within the title tags.

Regardless, the title tags still hold importance in three different ways.

• They are displayed as page title in search results (and influence user behavior with respect to clicking on particular results).
• Web browsers display them in naming open tabs; since the title is visible on hover, this is especially useful when too many tabs are open and only the favicon for each page (if available) is visible.
• As in search results, titles are visible when page links are posted on social media and this, too, conveys to the users what the link is about.

Unlike the keywords attribute, the description attribute is supported by most major search engines, like Yahoo! and Bing, while Google will fall back on this tag when information about the page itself is requested (e.g. using the related: query). The description attribute provides a concise explanation of a Web page's content. This allows the Web page authors to give a more meaningful description for listings than might be displayed if the search engine was unable to automatically create its own description based on the page content.[11] The description is often, but not always, displayed on search engine results pages, so it can affect click-through rates. While clicks for a result can be a positive sign of effective title and description writing, Google does not recognize this meta element as a ranking factor, so using target keyword phrases in that element will not help a site rank better. W3C doesn't specify the size of this description meta tag, but almost all search engines recommend it to be shorter than 160 characters of plain text.

The language attribute tells search engines what natural language the website is written in (e.g. English, Spanish or French), as opposed to the coding language (e.g. HTML). It is normally an IETF language tag for the language name. It is of most use when a website is written in multiple languages and can be included on each page to tell search engines in which language a particular page is written.[12] User-agents can (and do) use language information to select language-appropriate fonts, which improves the overall user experience of the page. [13]

The robots attribute, supported by several major search engines,[14] controls whether search engine spiders are allowed to index a page, or not, and whether they should follow links from a page, or not. The attribute can contain one or more comma-separate values. The noindex value prevents a page from being indexed, and nofollow prevents links from being crawled. Other values recognized by one or more search engines can influence how the engine indexes pages, and how those pages appear on the search results. These include noarchive, which instructs a search engine not to store an archived copy of the page, and nosnippet, which asks that the search engine not include a snippet from the page along with the page's listing in search results.[15]

Meta tags are one of the best options for preventing search engines from indexing content of a website.[16]

The search engines Google, Yahoo! and MSN use in some cases the title and abstract of the DMOZ (aka Open Directory Project) listing of a website for the title and/or description (also called snippet or abstract) in the search engine results pages (SERP). To give webmasters the option to specify that the Open Directory Project content should not be used for listings of their website, Microsoft introduced in May 2006 the new "NOODP" value for the "robots" element of the meta tags.[17] Google followed in July 2006[18] and Yahoo! in October 2006.[19]

The syntax is the same for all search engines who support the tag.

<meta name="robots" content="noodp" >

Webmasters can decide if they want to disallow the use of their ODP listing on a per search engine basis

Google:

<meta name="googlebot" content="noodp" >

Yahoo!

<meta name="Slurp" content="noodp" >

MSN and Live Search (via bingbot, previously msnbot):

<meta name="bingbot" content="noodp" >

Yahoo! puts content from their own Yahoo! directory next to the ODP listing. In 2007 they introduced a meta tag that lets web designers opt-out of this.[20]

Adding the NOYDIR tag to a page will prevent Yahoo! from displaying Yahoo! Directory titles and abstracts.

<meta name="robots" content="noydir" >
<meta name="Slurp" content="noydir" >

Yahoo! also introduced in May 2007 the attribute value: class="robots-nocontent".[21] This is not a meta tag, but an attribute and value, which can be used throughout Web page tags where needed. Content of the page where this attribute is being used will be ignored by the Yahoo! crawler and not included in the search engine's index.

Examples for the use of the robots-nocontent tag:

<div class="robots-nocontent">excluded content</div>
<span class="robots-nocontent">excluded content</span>
<p class="robots-nocontent">excluded content</p>

Google does not use HTML keyword or meta tag elements for indexing. The Director of Research at Google, Monika Henzinger, was quoted (in 2002) as saying, "Currently we don't trust metadata because we are afraid of being manipulated." [22] Other search engines developed techniques to penalize Web sites considered to be "cheating the system". For example, a Web site repeating the same meta keyword several times may have its ranking decreased by a search engine trying to eliminate this practice, though that is unlikely. It is more likely that a search engine will ignore the meta keyword element completely, and most do regardless of how many words are used in the element.

Google does, however, use meta tag elements for displaying site links. The title tags are used to create the link in search results:

<title>Site name - Page title - Keyword description</title>

The meta description often appears in Google search results to describe the link:

<meta name="description" content="A blurb to describe the content of the page appears here" >

Additionally, enterprise search startup Swiftype considers meta tags as a mechanism for signaling relevancy for their web site search engines, even introducing their own extension called Meta Tags 2.[23]