According to Wikipedia Search Engine Optimization (SEO) is the process of affecting the visibility of a website or a web page in a search engine's "natural" or un-paid ("organic") search results. In
general, the earlier (or higher ranked on the search results page), and more
frequently a site appears in the search results list, the more visitors it will
receive from the search engine's users. SEO may target different kinds of
search, including image search, local search, video search, academic search, news search and industry-specific vertical search engines. SEO is short for search engine optimization
or search engine
optimizer. Search engine optimization is
a methodology of strategies, techniques and tactics used to increase the amount
of visitors to a website by obtaining a high-ranking placement in the search
results page of a search engine (SERP)
-- including Google, Bing, Yahoo and other search engines. SEO helps to ensure that a site is accessible to a search engine and
improves the chances that the site will be found by the search engine.
History
Webmasters
and content providers began optimizing sites for search engines in the
mid-1990s, as the first search engines were cataloging the early Web. Initially, all webmasters needed to do was to submit the address of a page, or URL, to the various engines which would send a "spider" to "crawl" that page, extract links to other pages from it, and return information found on the page to be indexed.
The process involves a search engine spider downloading a page and
storing it on the search engine's own server, where a second program,
known as an indexer,
extracts various information about the page, such as the words it
contains and where these are located, as well as any weight for specific
words, and all links the page contains, which are then placed into a
scheduler for crawling at a later date.
Site owners started to recognize the value of having their sites highly ranked and visible in search engine results, creating an opportunity for both white hat and black hat SEO practitioners. According to industry analyst Danny Sullivan, the phrase "search engine optimization" probably came into use in 1997. On May 2, 2007, Jason Gambert attempted to trademark the term SEO by convincing the Trademark Office in Arizona that SEO is a "process" involving manipulation of keywords, and not a "marketing service." The reviewing attorney basically bought his incoherent argument that while "SEO" can't be trademarked when it refers to a generic process of manipulated keywords, it can be a service mark for providing "marketing services...in the field of computers."
Early versions of search algorithms relied on webmaster-provided information such as the keyword meta tag, or index files in engines like ALIWEB. Meta tags provide a guide to each page's content. Using meta data to index pages was found to be less than reliable, however, because the webmaster's choice of keywords in the meta tag could potentially be an inaccurate representation of the site's actual content. Inaccurate, incomplete, and inconsistent data in meta tags could and did cause pages to rank for irrelevant searches. Web content providers also manipulated a number of attributes within the HTML source of a page in an attempt to rank well in search engines.
By relying so much on factors such as keyword density which were exclusively within a webmaster's control, early search engines suffered from abuse and ranking manipulation. To provide better results to their users, search engines had to adapt to ensure their results pages showed the most relevant search results, rather than unrelated pages stuffed with numerous keywords by unscrupulous webmasters. Since the success and popularity of a search engine is determined by its ability to produce the most relevant results to any given search, poor quality or irrelevant search results could lead users to find other search sources. Search engines responded by developing more complex ranking algorithms, taking into account additional factors that were more difficult for webmasters to manipulate. Graduate students at Stanford University, Larry Page and Sergey Brin, developed "Backrub," a search engine that relied on a mathematical algorithm to rate the prominence of web pages. The number calculated by the algorithm, PageRank, is a function of the quantity and strength of inbound links. PageRank estimates the likelihood that a given page will be reached by a web user who randomly surfs the web, and follows links from one page to another. In effect, this means that some links are stronger than others, as a higher PageRank page is more likely to be reached by the random surfer.
Page and Brin founded Google in 1998. Google attracted a loyal following among the growing number of Internet users, who liked its simple design. Off-page factors (such as PageRank and hyperlink analysis) were considered as well as on-page factors (such as keyword frequency, meta tags, headings, links and site structure) to enable Google to avoid the kind of manipulation seen in search engines that only considered on-page factors for their rankings. Although PageRank was more difficult to game, webmasters had already developed link building tools and schemes to influence the Inktomi search engine, and these methods proved similarly applicable to gaming PageRank. Many sites focused on exchanging, buying, and selling links, often on a massive scale. Some of these schemes, or link farms, involved the creation of thousands of sites for the sole purpose of link spamming.
By 2004, search engines had incorporated a wide range of undisclosed factors in their ranking algorithms to reduce the impact of link manipulation. In June 2007, The New York Times' Saul Hansell stated Google ranks sites using more than 200 different signals. The leading search engines, Google, Bing, and Yahoo, do not disclose the algorithms they use to rank pages. Some SEO practitioners have studied different approaches to search engine optimization, and have shared their personal opinions Patents related to search engines can provide information to better understand search engines.
In 2005, Google began personalizing search results for each user. Depending on their history of previous searches, Google crafted results for logged in users. In 2008, Bruce Clay said that "ranking is dead" because of personalized search. He opined that it would become meaningless to discuss how a website ranked, because its rank would potentially be different for each user and each search.
In 2007, Google announced a campaign against paid links that transfer PageRank. On June 15, 2009, Google disclosed that they had taken measures to mitigate the effects of PageRank sculpting by use of the nofollow attribute on links. Matt Cutts,
a well-known software engineer at Google, announced that Google Bot
would no longer treat nofollowed links in the same way, in order to
prevent SEO service providers from using nofollow for PageRank
sculpting.
As a result of this change the usage of nofollow leads to evaporation
of pagerank. In order to avoid the above, SEO engineers developed
alternative techniques that replace nofollowed tags with obfuscated Javascript and thus permit PageRank sculpting. Additionally several solutions have been suggested that include the usage of iframes, Flash and Javascript.
In December 2009, Google announced it would be using the web search history of all its users in order to populate search results.
On June 8, 2010 a new web indexing system called Google Caffeine
was announced. Designed to allow users to find news results, forum
posts and other content much sooner after publishing than before, Google
caffeine was a change to the way Google updated its index in order to
make things show up quicker on Google than before. According to Carrie
Grimes, the software engineer who announced Caffeine for Google,
"Caffeine provides 50 percent fresher results for web searches than our
last index..."
Google Instant, real-time-search, was introduced in late 2010 in an attempt to make search results more timely and relevant. Historically site administrators have spent months or even years optimizing a website to increase search rankings. With the growth in popularity of social media sites and blogs the leading engines made changes to their algorithms to allow fresh content to rank quickly within the search results.
In February 2011, Google announced the Panda update, which penalizes websites containing content duplicated from other websites and sources. Historically websites have copied content from one another and benefited in search engine rankings by engaging in this practice, however Google implemented a new system which punishes sites whose content is not unique.
In April 2012, Google launched the Google Penguin
update the goal of which was to penalize websites that used
manipulative techniques to improve their rankings on the search engine.
In September 2013, Google released the Google Hummingbird update, an algorithm change designed to improve Google's natural language processing and semantic understanding of web pages.
Relationship With Search Engine
By 1997, search engine designers recognized that webmasters were making efforts to rank well in their search engines, and that some webmasters were even manipulating their rankings in search results by stuffing pages with excessive or irrelevant keywords. Early search engines, such as Altavista and Infoseek, adjusted their algorithms in an effort to prevent webmasters from manipulating rankings.
In 2005, an annual conference, AIRWeb, Adversarial Information Retrieval on the Web was created to bring together practitioners and researchers concerned with search engine optimisation and related topics.
Companies that employ overly aggressive techniques can get their client websites banned from the search results. In 2005, the Wall Street Journal reported on a company, Traffic Power, which allegedly used high-risk techniques and failed to disclose those risks to its clients. Wired magazine reported that the same company sued blogger and SEO Aaron Wall for writing about the ban. Google's Matt Cutts later confirmed that Google did in fact ban Traffic Power and some of its clients.
Some search engines have also reached out to the SEO industry, and
are frequent sponsors and guests at SEO conferences, chats, and
seminars. Major search engines provide information and guidelines to
help with site optimization. Google has a Sitemaps
program to help webmasters learn if Google is having any problems
indexing their website and also provides data on Google traffic to the
website. Bing Webmaster Tools
provides a way for webmasters to submit a sitemap and web feeds, allows
users to determine the crawl rate, and track the web pages index
status.
Method
Getting indexed
The leading search engines, such as Google, Bing and Yahoo!, use crawlers
to find pages for their algorithmic search results. Pages that are
linked from other search engine indexed pages do not need to be
submitted because they are found automatically. Two major directories,
the Yahoo Directory and DMOZ both require manual submission and human editorial review. Google offers Google Webmaster Tools, for which an XML Sitemap
feed can be created and submitted for free to ensure that all pages are
found, especially pages that are not discoverable by automatically
following links. Yahoo! formerly operated a paid submission service that guaranteed crawling for a cost per click; this was discontinued in 2009.
Search engine crawlers may look at a number of different factors when crawling a site. Not every page is indexed by the search engines. Distance of pages from the root directory of a site may also be a factor in whether or not pages get crawled.
Preventing crawling
To avoid undesirable content in the search indexes, webmasters can
instruct spiders not to crawl certain files or directories through the
standard robots.txt
file in the root directory of the domain. Additionally, a page can be
explicitly excluded from a search engine's database by using a meta tag specific to robots. When a search engine visits a site, the robots.txt located in the root directory
is the first file crawled. The robots.txt file is then parsed, and will
instruct the robot as to which pages are not to be crawled. As a search
engine crawler may keep a cached copy of this file, it may on occasion
crawl pages a webmaster does not wish crawled. Pages typically prevented
from being crawled include login specific pages such as shopping carts
and user-specific content such as search results from internal searches.
In March 2007, Google warned webmasters that they should prevent
indexing of internal search results because those pages are considered
search spam.
Increasing prominence
A variety of methods can increase the prominence of a webpage within the search results. Cross linking between pages of the same website to provide more links to most important pages may improve its visibility.
Writing content that includes frequently searched keyword phrase, so as
to be relevant to a wide variety of search queries will tend to
increase traffic.
Updating content so as to keep search engines crawling back frequently
can give additional weight to a site. Adding relevant keywords to a web
page's meta data, including the title tag and meta description, will tend to improve the relevancy of a site's search listings, thus increasing traffic. URL normalization of web pages accessible via multiple urls, using the canonical link element or via 301 redirects can help make sure links to different versions of the url all count towards the page's link popularity score.
SEO techniques can be classified into two broad categories: techniques
that search engines recommend as part of good design, and those
techniques of which search engines do not approve. The search engines
attempt to minimize the effect of the latter, among them spamdexing. Industry commentators have classified these methods, and the practitioners who employ them, as either white hat SEO, or black hat SEO.
White Hat SEO
In search engine optimization (SEO)
terminology, white hat SEO refers to the usage of optimization
strategies, techniques and tactics that focus on a human audience
opposed to search engines and completely follows search engine rules and policies. For example, a website
that is optimized for search engines, yet focuses on relevancy and
organic ranking is considered to be optimized using White Hat SEO
practices. Some examples of White Hat SEO techniques include using keywords and keyword analysis, backlinking, link building to improve link popularity, and writing content for human readers. White Hat SEO is more frequently used by those who intend to make a long-term investment on their website. Also called Ethical SEO.
Black Hat SEO
In search engine optimization (SEO)
terminology, black hat SEO refers to the use of aggressive SEO
strategies, techniques and tactics that focus only on search engines and
not a human audience, and usually does not obey search engines
guidelines. Some examples of black hat SEO techniques include keyword stuffing, invisible text, doorway
pages, adding unrelated keywords to the page content or page swapping
(changing the webpage entirely after it has been ranked by search
engines). Black hat SEO is more frequently used by those who are looking for a quick financial return on their Web site, rather than a long-term investment on their Web site. Black hat SEO can possibly result in your Web site being banned from a search engine,
however since the focus is usually on quick high return business
models, most experts who use Black Hat SEO tactics consider being banned
from search engines a somewhat irrelevant risk.
SEO as a Marketing Strategy
SEO is not an appropriate strategy for every website, and other
Internet marketing strategies can be more effective like paid
advertising through pay per click (PPC) campaigns, depending on the site operator's goals. A successful Internet marketing campaign may also depend upon building
high quality web pages to engage and persuade, setting up analytics programs to enable site owners to measure results, and improving a site's conversion rate.
SEO may generate an adequate return on investment. However, search engines are not paid for organic search traffic, their algorithms change, and there are no guarantees of continued referrals. Due to this lack of guarantees and certainty, a business that relies heavily on search engine traffic can suffer major losses if the search engines stop sending visitors. Search engines can change their algorithms, impacting a website's placement, possibly resulting in a serious loss of traffic. According to Google's CEO, Eric Schmidt, in 2010, Google made over 500 algorithm changes – almost 1.5 per day. It is considered wise business practice for website operators to liberate themselves from dependence on search engine traffic.
